GHSA-468C-VQ7P-GH64

Vulnerability from github – Published: 2026-05-20 15:35 – Updated: 2026-05-20 15:35
VLAI
Summary
Plug: Unbounded buffer accumulation in multipart header parsing causes denial of service
Details

Summary

An Allocation of Resources Without Limits or Throttling vulnerability in Plug.Conn.read_part_headers/2 allows an unauthenticated attacker to exhaust server memory by sending a crafted multipart/form-data request, causing a denial of service.

Details

Plug.Conn.read_part_headers/2 in lib/plug/conn.ex does not obey its :length parameter. There is no upper bound on the size of the accumulated buffer. By contrast, the sibling function read_part_body has an explicit byte_size(acc) > length guard that stops accumulation once a limit is reached. No such guard exists in read_part_headers.

Impact

This is a denial-of-service vulnerability. Any application using Plug.Parsers with the :multipart parser, or calling Plug.Conn.read_part_headers/2 directly, is affected. An unauthenticated remote attacker can trigger the issue by sending crafted HTTP requests with no special privileges.

References

  • Intro Commit: https://github.com/elixir-plug/plug/commit/c52b2f32c90bccd718202bafccb5f95594e30183
  • Patch Commit: https://github.com/elixir-plug/plug/commit/d878b42efea9f12b243dc3e362a2ed048a798203
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
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{
  "affected": [
    {
      "package": {
        "ecosystem": "Hex",
        "name": "plug"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.4.0"
            },
            {
              "fixed": "1.15.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Hex",
        "name": "plug"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.16.0"
            },
            {
              "fixed": "1.16.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Hex",
        "name": "plug"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.17.0"
            },
            {
              "fixed": "1.17.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Hex",
        "name": "plug"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.18.0"
            },
            {
              "fixed": "1.18.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Hex",
        "name": "plug"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.19.0"
            },
            {
              "fixed": "1.19.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-8468"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-770"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-20T15:35:13Z",
    "nvd_published_at": "2026-05-14T11:16:18Z",
    "severity": "HIGH"
  },
  "details": "### Summary\n\nAn Allocation of Resources Without Limits or Throttling vulnerability in `Plug.Conn.read_part_headers/2` allows an unauthenticated attacker to exhaust server memory by sending a crafted `multipart/form-data` request, causing a denial of service.\n\n### Details\n\n`Plug.Conn.read_part_headers/2` in `lib/plug/conn.ex` does not obey its `:length` parameter. There is no upper bound on the size of the accumulated buffer. By contrast, the sibling function `read_part_body` has an explicit `byte_size(acc) \u003e length` guard that stops accumulation once a limit is reached. No such guard exists in `read_part_headers`.\n\n### Impact\n\nThis is a denial-of-service vulnerability. Any application using `Plug.Parsers` with the `:multipart` parser, or calling `Plug.Conn.read_part_headers/2` directly, is affected. An unauthenticated remote attacker can trigger the issue by sending crafted HTTP requests with no special privileges.\n\n### References\n\n* Intro Commit: https://github.com/elixir-plug/plug/commit/c52b2f32c90bccd718202bafccb5f95594e30183\n* Patch Commit: https://github.com/elixir-plug/plug/commit/d878b42efea9f12b243dc3e362a2ed048a798203",
  "id": "GHSA-468c-vq7p-gh64",
  "modified": "2026-05-20T15:35:13Z",
  "published": "2026-05-20T15:35:13Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/elixir-plug/plug/security/advisories/GHSA-468c-vq7p-gh64"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-8468"
    },
    {
      "type": "WEB",
      "url": "https://github.com/elixir-plug/plug/commit/2cb7958d33030aa826b0c7404375844d4593d43a"
    },
    {
      "type": "WEB",
      "url": "https://github.com/elixir-plug/plug/commit/33858427c7f2737d560a2e40a0c9a9270d77d1d7"
    },
    {
      "type": "WEB",
      "url": "https://github.com/elixir-plug/plug/commit/aa69c5ece99c40ded88b8c6581ecc86664b0b734"
    },
    {
      "type": "WEB",
      "url": "https://github.com/elixir-plug/plug/commit/d5dfffe25e975585227b1b85d247b0d14164bc45"
    },
    {
      "type": "WEB",
      "url": "https://github.com/elixir-plug/plug/commit/df812a1527bae9e941965e897308a2b8bbf83a94"
    },
    {
      "type": "WEB",
      "url": "https://cna.erlef.org/cves/CVE-2026-8466.html"
    },
    {
      "type": "WEB",
      "url": "https://cna.erlef.org/cves/CVE-2026-8468.html"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/elixir-plug/plug"
    },
    {
      "type": "WEB",
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-8468"
    }
  ],
  "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": "Plug: Unbounded buffer accumulation in multipart header parsing causes denial of service"
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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  • 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.
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  • 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.