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Unbounded buffer accumulation in multipart header parsing causes denial of service in plug

Type: advisorySources: OSV

Allocation of Resources Without Limits or Throttling vulnerability in plug_project plug allows denial of service via unbounded buffer accumulation in multipart header parsing. 'Elixir.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. An unauthenticated remote attacker can exhaust server memory by sending a crafted multipart/form-data request, causing a denial of service. This issue affects plug from 1.4.0 before 1.15.4, 1.16.3, 1.17.1, 1.18.2, and 1.19.2.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-8468
Confirmed fixed CVEs
Not specified
Updated in this feed
4 Nov 2026, 21:03 UTC · Revision 1

Source evidence

Unbounded buffer accumulation in multipart header parsing causes denial of service in plug

core-osv · Original source

Published 14 May 2026, 10:29 UTC

Allocation of Resources Without Limits or Throttling vulnerability in plug_project plug allows denial of service via unbounded buffer accumulation in multipart header parsing. 'Elixir.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. An unauthenticated remote attacker can exhaust server memory by sending a crafted multipart/form-data request, causing a denial of service. This issue affects plug from 1.4.0 before 1.15.4, 1.16.3, 1.17.1, 1.18.2, and 1.19.2.

osv:CVE-2026-8468
Complete source record
{
  "id": "59aae26756e9519a51f918b29b0f70322fa3f5e64135715b94b1875279ec1fb9",
  "url": "https://osv.dev/vulnerability/CVE-2026-8468",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Unbounded buffer accumulation in multipart header parsing causes denial of service in plug",
    "summary": "Allocation of Resources Without Limits or Throttling vulnerability in plug_project plug allows denial of service via unbounded buffer accumulation in multipart header parsing. 'Elixir.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. An unauthenticated remote attacker can exhaust server memory by sending a crafted multipart/form-data request, causing a denial of service. This issue affects plug from 1.4.0 before 1.15.4, 1.16.3, 1.17.1, 1.18.2, and 1.19.2.",
    "evidence": "osv:CVE-2026-8468",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-8468",
      "aliases": [
        "CVE-2026-8468",
        "EEF-CVE-2026-8468",
        "GHSA-468c-vq7p-gh64"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "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"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/elixir-plug/plug",
              "type": "GIT",
              "events": [
                {
                  "introduced": "f16a7526eb87c8953648dea2b7c57fe0c31e57f7"
                },
                {
                  "fixed": "2cb7958d33030aa826b0c7404375844d4593d43a"
                },
                {
                  "fixed": "33858427c7f2737d560a2e40a0c9a9270d77d1d7"
                },
                {
                  "fixed": "aa69c5ece99c40ded88b8c6581ecc86664b0b734"
                },
                {
                  "fixed": "d5dfffe25e975585227b1b85d247b0d14164bc45"
                },
                {
                  "fixed": "df812a1527bae9e941965e897308a2b8bbf83a94"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "1.4.0"
                      },
                      {
                        "fixed": "1.15.4"
                      }
                    ],
                    "source": "DESCRIPTION"
                  },
                  {
                    "range": [
                      {
                        "fixed": "2cb7958d33030aa826b0c7404375844d4593d43a"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "33858427c7f2737d560a2e40a0c9a9270d77d1d7"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "aa69c5ece99c40ded88b8c6581ecc86664b0b734"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "d5dfffe25e975585227b1b85d247b0d14164bc45"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "df812a1527bae9e941965e897308a2b8bbf83a94"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v1.15.3",
            "v1.16.2",
            "v1.17.0",
            "v1.18.1",
            "v1.19.1",
            "v1.18.0",
            "v1.16.1",
            "v1.16.0",
            "v1.15.2",
            "v1.15.1",
            "v1.15.0",
            "v1.14.2",
            "v1.14.1",
            "v1.14.0",
            "v1.13.5",
            "v1.13.4",
            "v1.13.3",
            "v1.13.2",
            "v1.13.1",
            "v1.13.0",
            "v1.12.1",
            "v1.12.0",
            "v1.11.1",
            "v1.11.0",
            "v1.10.3",
            "v1.10.2",
            "v1.10.1",
            "v1.10.0",
            "v1.9.0",
            "v1.8.2",
            "v1.8.1",
            "v1.8.0",
            "v1.7.2",
            "v1.7.1",
            "v1.7.0",
            "v1.6.1",
            "v1.6.0",
            "v1.5.1",
            "v1.5.0",
            "v1.5.0-rc.2",
            "v1.5.0-rc.1",
            "v1.4.3",
            "v1.5.0-rc.0",
            "v1.4.2",
            "v1.4.1",
            "v1.4.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-8468.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:39.824240902Z",
      "provider": "osv",
      "references": [
        "https://cna.erlef.org/cves/CVE-2026-8466.html",
        "https://cna.erlef.org/cves/CVE-2026-8468.html",
        "https://github.com",
        "https://osv.dev/vulnerability/EEF-CVE-2026-8468",
        "https://repo.hex.pm",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/8xxx/CVE-2026-8468.json",
        "https://github.com/elixir-plug/plug/security/advisories/GHSA-468c-vq7p-gh64",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-8468",
        "https://github.com/elixir-plug/plug/commit/2cb7958d33030aa826b0c7404375844d4593d43a",
        "https://github.com/elixir-plug/plug/commit/33858427c7f2737d560a2e40a0c9a9270d77d1d7",
        "https://github.com/elixir-plug/plug/commit/aa69c5ece99c40ded88b8c6581ecc86664b0b734",
        "https://github.com/elixir-plug/plug/commit/d5dfffe25e975585227b1b85d247b0d14164bc45",
        "https://github.com/elixir-plug/plug/commit/df812a1527bae9e941965e897308a2b8bbf83a94",
        "https://github.com/elixir-plug/plug"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-770"
        ],
        "cna_assigner": "EEF",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/8xxx/CVE-2026-8468.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-8468",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 507005,
  "published_at": "2026-05-14T10:29:51.062+00:00"
}