{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:elixir-plug:plug.cowboy:*:*:*:*:*:*:*:*",
            "extracted_events": [
              {
                "introduced": "2.0.0"
              },
              {
                "fixed": "2.8.1"
              }
            ],
            "source": [
              "CPE_RANGE",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "8d60f2912743834b48544e6fd1f01f832d660cb1"
            },
            {
              "fixed": "fd0841f4ef974b95a5050a2b5959585c56fb3776"
            },
            {
              "fixed": "bfb34cb45eb354e56437f7023fb306de1bf9c19b"
            }
          ],
          "repo": "https://github.com/elixir-plug/plug_cowboy",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-q8x4-x7mp-5vg2"
  ],
  "database_specific": {
    "cna_assigner": "EEF",
    "cwe_ids": [
      "CWE-770"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/32xxx/CVE-2026-32688.json",
    "unresolved_ranges": [
      {
        "extracted_events": [
          {
            "introduced": "12ecfd024bb179d48b018fecf074e43fe6a19c83"
          },
          {
            "fixed": "bfb34cb45eb354e56437f7023fb306de1bf9c19b"
          }
        ],
        "source": "AFFECTED_FIELD"
      }
    ]
  },
  "details": "Allocation of Resources Without Limits or Throttling vulnerability in elixir-plug plug_cowboy allows unauthenticated remote denial of service via atom table exhaustion.\n\nPlug.Cowboy.Conn.conn/1 in lib/plug/cowboy/conn.ex calls String.to_atom/1 on the value returned by :cowboy_req.scheme/1. For HTTP/2 connections, cowlib passes the client-supplied :scheme pseudo-header value through verbatim without validation. Each unique value permanently allocates a new entry in the BEAM atom table. Since atoms are never garbage-collected and the atom table has a fixed limit (default 1,048,576), an unauthenticated attacker can exhaust the table by sending HTTP/2 requests with unique :scheme values, causing the Erlang VM to abort with system_limit and taking down the entire node.\n\nThis vulnerability does not affect HTTP/1.1, where cowboy derives the scheme from the listener type rather than from a client-supplied header.\n\nThis issue affects plug_cowboy: from 2.0.0 before 2.8.1.",
  "id": "CVE-2026-32688",
  "modified": "2026-07-08T05:37:31.477426557Z",
  "published": "2026-04-27T13:45:35.160Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://cna.erlef.org/cves/CVE-2026-32688.html"
    },
    {
      "type": "WEB",
      "url": "https://github.com"
    },
    {
      "type": "WEB",
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-32688"
    },
    {
      "type": "WEB",
      "url": "https://repo.hex.pm"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/32xxx/CVE-2026-32688.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/elixir-plug/plug_cowboy/security/advisories/GHSA-q8x4-x7mp-5vg2"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-32688"
    },
    {
      "type": "FIX",
      "url": "https://github.com/elixir-plug/plug_cowboy/commit/bfb34cb45eb354e56437f7023fb306de1bf9c19b"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/elixir-plug/plug_cowboy"
    }
  ],
  "schema_version": "1.7.5",
  "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Atom table exhaustion via HTTP/2 :scheme pseudo-header in plug_cowboy"
}