Vulnerability-Lookup

GHSA-GRP7-V8XH-RJ7H

Vulnerability from github – Published: 2026-08-25 18:09 – Updated: 2026-08-25 18:09

Summary

gRPC Erlang package vulnerable to Remote Code Execution with attacker-controlled gRPC payloads

Details

Summary

GRPC.Codec.Erlpack.decode/2 calls :erlang.binary_to_term/1 directly on the raw gRPC message body without the :safe option. Any unauthenticated peer that can reach a gRPC endpoint with Content-Type: application/grpc+erlpack can crash the entire BEAM node via atom table exhaustion or, if a decoded fun term flows into a call site that invokes it, achieve remote code execution inside the server process.

Details

Root cause — lib/grpc/codec/erlpack.ex implements decode/2 as a bare :erlang.binary_to_term(binary) call with no :safe flag, no size limit, and no type validation. This has two independent exploitation paths:

1. DoS via atom exhaustion — BEAM atoms are never garbage-collected and the global atom table is bounded (~1,048,576 entries). A crafted payload encoding large numbers of fresh atoms saturates the table and crashes the entire VM, taking down all applications on the node.

2. RCE via fun materialization — Without :safe, binary_to_term/1 reconstructs fun and external-fun terms from wire data. If the decoded value reaches any call site that applies it (e.g. Enum.map, Task.async, direct invocation), attacker-controlled code executes inside the server process.

Configuration requirement: GRPC.Codec.Erlpack is not registered by default and must be explicitly added to the server's codecs option.

PoC

Start a gRPC server with codecs: [GRPC.Codec.Erlpack].
Open an HTTP/2 connection to the server.
Send a gRPC-framed POST to any RPC path with Content-Type: application/grpc+erlpack and a body of :erlang.term_to_binary(fn -> <malicious_code> end).
The server's decode/2 materializes the fun; any downstream call site that invokes the decoded value executes the attacker's code.
For DoS only: send payloads encoding fresh atoms in a loop until the atom table is exhausted and the VM crashes.

Impact

Affects grpc ≥ 0.4.0. Any server that explicitly registers GRPC.Codec.Erlpack is vulnerable to unauthenticated node-level DoS and potentially RCE.

References

Introduction commit: https://github.com/elixir-grpc/grpc/commit/25bcc569fe2cc4478531a6c546c923205fc751c9
Patch commit: https://github.com/elixir-grpc/grpc/commit/272a97a5ea1b46af1819f14a831fcf35fc91f992

Severity

9.2 (Critical)


                  
                    CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Show details on source website

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Hex",
        "name": "grpc"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.4.0"
            },
            {
              "fixed": "1.0.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-48853"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-502",
      "CWE-770"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-08-25T18:09:53Z",
    "nvd_published_at": "2026-06-15T23:16:45Z",
    "severity": "CRITICAL"
  },
  "details": "### Summary\n\n`GRPC.Codec.Erlpack.decode/2` calls `:erlang.binary_to_term/1` directly on the raw gRPC message body without the `:safe` option. Any unauthenticated peer that can reach a gRPC endpoint with `Content-Type: application/grpc+erlpack` can crash the entire BEAM node via atom table exhaustion or, if a decoded fun term flows into a call site that invokes it, achieve remote code execution inside the server process.\n\n### Details\n\n**Root cause** \u2014 `lib/grpc/codec/erlpack.ex` implements `decode/2` as a bare `:erlang.binary_to_term(binary)` call with no `:safe` flag, no size limit, and no type validation. This has two independent exploitation paths:\n\n**1. DoS via atom exhaustion** \u2014 BEAM atoms are never garbage-collected and the global atom table is bounded (~1,048,576 entries). A crafted payload encoding large numbers of fresh atoms saturates the table and crashes the entire VM, taking down all applications on the node.\n\n**2. RCE via fun materialization** \u2014 Without `:safe`, `binary_to_term/1` reconstructs fun and external-fun terms from wire data. If the decoded value reaches any call site that applies it (e.g. `Enum.map`, `Task.async`, direct invocation), attacker-controlled code executes inside the server process.\n\n**Configuration requirement:** `GRPC.Codec.Erlpack` is not registered by default and must be explicitly added to the server\u0027s `codecs` option.\n\n### PoC\n\n1. Start a gRPC server with `codecs: [GRPC.Codec.Erlpack]`.\n2. Open an HTTP/2 connection to the server.\n3. Send a gRPC-framed POST to any RPC path with `Content-Type: application/grpc+erlpack` and a body of `:erlang.term_to_binary(fn -\u003e \u003cmalicious_code\u003e end)`.\n4. The server\u0027s `decode/2` materializes the fun; any downstream call site that invokes the decoded value executes the attacker\u0027s code.\n5. For DoS only: send payloads encoding fresh atoms in a loop until the atom table is exhausted and the VM crashes.\n\n### Impact\n\nAffects `grpc` \u2265 0.4.0. Any server that explicitly registers `GRPC.Codec.Erlpack` is vulnerable to unauthenticated node-level DoS and potentially RCE.\n\n### References\n\n* Introduction commit: https://github.com/elixir-grpc/grpc/commit/25bcc569fe2cc4478531a6c546c923205fc751c9\n* Patch commit: https://github.com/elixir-grpc/grpc/commit/272a97a5ea1b46af1819f14a831fcf35fc91f992",
  "id": "GHSA-grp7-v8xh-rj7h",
  "modified": "2026-08-25T18:09:53Z",
  "published": "2026-08-25T18:09:53Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/elixir-grpc/grpc/security/advisories/GHSA-grp7-v8xh-rj7h"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-48853"
    },
    {
      "type": "WEB",
      "url": "https://github.com/elixir-grpc/grpc/pull/540"
    },
    {
      "type": "WEB",
      "url": "https://github.com/elixir-grpc/grpc/commit/272a97a5ea1b46af1819f14a831fcf35fc91f992"
    },
    {
      "type": "WEB",
      "url": "https://cna.erlef.org/cves/CVE-2026-48853.html"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/elixir-grpc/grpc"
    },
    {
      "type": "WEB",
      "url": "https://github.com/elixir-grpc/grpc/releases/tag/v1.0.0"
    },
    {
      "type": "WEB",
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-48853"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "gRPC Erlang package vulnerable to Remote Code Execution with attacker-controlled gRPC payloads"
}

CVE-2026-48853 (GCVE-0-2026-48853)

Vulnerability from cvelistv5 – Published: 2026-06-15 21:56 – Updated: 2026-06-17 04:47

Title

Remote code execution and denial of service via unsafe Erlang term deserialization in elixir-grpc/grpc

Summary

Deserialization of Untrusted Data and Allocation of Resources Without Limits or Throttling vulnerabilities in elixir-grpc grpc allow unauthenticated attackers to crash the BEAM node via atom table exhaustion and, when a decoded term flows into a call site that invokes it, achieve remote code execution on the server. 'Elixir.GRPC.Codec.Erlpack':decode/2 (lib/grpc/codec/erlpack.ex) calls :erlang.binary_to_term/1 on the raw gRPC message body without the :safe option, no size bound, and no type guard. Any unauthenticated peer that sends a request with Content-Type: application/grpc+erlpack can send a crafted payload that mints arbitrary new atoms (which are never garbage-collected, exhausting the bounded atom table and crashing the VM) or that encodes a fun term which, if applied anywhere downstream, executes attacker-controlled code inside the server process. This issue affects grpc from 0.4.0 before 1.0.0.

Severity

9.2 (Critical)


                        
                          CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

SSVC

Exploitation: poc Automatable: yes Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-06-16 14:44 UTC

CWE

CWE-502 - Deserialization of Untrusted Data
CWE-770 - Allocation of Resources Without Limits or Throttling

Assigner

EEF mitre root

References

4 references

URL	Tags
https://github.com/elixir-grpc/grpc/security/advi…	vendor-advisoryrelated
https://cna.erlef.org/cves/CVE-2026-48853.html	related
https://osv.dev/vulnerability/EEF-CVE-2026-48853	related
https://github.com/elixir-grpc/grpc/commit/272a97…	patch

Impacted products

2 products

Vendor	Product	Version
elixir-grpc	grpc	Affected: 0.4.0 , < 1.0.0 (semver) cpe:2.3:a:elixir-grpc:grpc::::::::
elixir-grpc	grpc	Affected: 25bcc569fe2cc4478531a6c546c923205fc751c9 , < 272a97a5ea1b46af1819f14a831fcf35fc91f992 (git) cpe:2.3:a:elixir-grpc:grpc::::::::

Credits

Peter Ullrich Paulo Valente Jonatan Männchen

Show details on NVD website

JSON

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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

GHSA-GRP7-V8XH-RJ7H

Summary

Details

PoC

Impact

References

CVE-2026-48853 (GCVE-0-2026-48853)

Tags

Sightings

Nomenclature

Related by attack behaviour