{
  "affected": [
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:12",
        "name": "libevent"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.1.12-stable-8+deb12u1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:13",
        "name": "libevent"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.1.13-stable-1~deb13u1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:14",
        "name": "libevent"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.1.13-stable-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "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": "DEBIAN-CVE-2026-63379",
  "modified": "2026-09-18T15:47:29.632027552Z",
  "published": "2026-08-20T18:16:35.200Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security-tracker.debian.org/tracker/CVE-2026-63379"
    }
  ],
  "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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ],
  "upstream": [
    "CVE-2026-63379"
  ]
}