{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "2.1.13"
              },
              {
                "introduced": "2.2.0-alpha"
              },
              {
                "fixed": "2.2.2-alpha"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "79ddfb460847999b807cba76d04e73891f29c6ee"
            },
            {
              "fixed": "df3ecad3a040fd6d4fad4287defe113395de6fd7"
            },
            {
              "fixed": "87e8e44fa774e9677b089b1a5114ee68aefa1636"
            },
            {
              "fixed": "b847071141b3827900d536594ec9045eb0a4c485"
            }
          ],
          "repo": "https://github.com/libevent/libevent",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-2gmv-p5m7-98p6"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-444"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63379.json"
  },
  "details": "Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent processes chunked HTTP trailers in http.c through evhttp_read_trailer and merges them into request headers. The fix introduces evhttp_parse_headers_impl_ and a temporary trailer header list. An unauthenticated remote attacker can place security-sensitive fields in trailers so that an upstream proxy and the libevent application interpret different effective headers, enabling header smuggling, authorization bypass, proxy-header spoofing, or cache poisoning. The fix parses trailers into a temporary header list and discards them instead of merging them into req-\u003einput_headers. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.",
  "id": "CVE-2026-63379",
  "modified": "2026-08-22T03:31:09.608586585Z",
  "published": "2026-08-20T17:55:00.789Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/libevent/libevent/releases/tag/release-2.1.13-stable"
    },
    {
      "type": "WEB",
      "url": "https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63379.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/libevent/libevent/security/advisories/GHSA-2gmv-p5m7-98p6"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-63379"
    },
    {
      "type": "FIX",
      "url": "https://github.com/libevent/libevent/commit/87e8e44fa774e9677b089b1a5114ee68aefa1636"
    },
    {
      "type": "FIX",
      "url": "https://github.com/libevent/libevent/commit/b847071141b3827900d536594ec9045eb0a4c485"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Libevent: HTTP Header smuggling"
}