cve-2026-63385

{
  "cvss": 9.2,
  "datePublished": "2026-08-20T18:16:36.543",
  "dateUpdated": "2026-10-26T10:10:00.140",
  "description": "Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has two HTTP parsing weaknesses in http.c. evhttp_decode_uri_internal decodes percent-encoded %00 bytes into literal NUL characters, which can cause downstream C string operations to truncate a path and bypass validation performed on a different representation. evhttp_header_is_valid_value also accepts obsolete line folding in header values containing carriage return or line feed characters, allowing a proxy and libevent to interpret headers differently and enabling header injection or access control bypass. The CRLF header acceptance is fixed in versions 2.1.13 and 2.2.2-alpha, but the reviewed patches do not clearly remediate the URI NUL-truncation condition.",
  "id": "CVE-2026-63385",
  "raw": {
    "affected": [
      {
        "affectedData": [
          {
            "product": "libevent",
            "vendor": "libevent",
            "versions": [
              {
                "status": "affected",
                "version": ">= 2.2.0-alpha, < 2.2.2-alpha"
              },
              {
                "status": "affected",
                "version": "< 2.1.13"
              }
            ]
          }
        ],
        "source": "security-advisories@github.com"
      }
    ],
    "cveTags": [],
    "descriptions": [
      {
        "lang": "en",
        "value": "Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has two HTTP parsing weaknesses in http.c. evhttp_decode_uri_internal decodes percent-encoded %00 bytes into literal NUL characters, which can cause downstream C string operations to truncate a path and bypass validation performed on a different representation. evhttp_header_is_valid_value also accepts obsolete line folding in header values containing carriage return or line feed characters, allowing a proxy and libevent to interpret headers differently and enabling header injection or access control bypass. The CRLF header acceptance is fixed in versions 2.1.13 and 2.2.2-alpha, but the reviewed patches do not clearly remediate the URI NUL-truncation condition."
      },
      {
        "lang": "es",
        "value": "Libevent es una biblioteca de notificación de eventos. Antes de 2.1.13 y 2.2.2-alpha, libevent tiene dos debilidades de análisis HTTP en http.c. evhttp_decode_uri_internal decodifica bytes %00 codificados por porcentaje en caracteres NUL literales, lo que puede causar que las operaciones de cadena C posteriores trunquen una ruta y omitan la validación realizada en una representación diferente. evhttp_header_is_valid_value también acepta el plegado de línea obsoleto en valores de encabezado que contienen caracteres de retorno de carro o salto de línea, lo que permite que un proxy y libevent interpreten los encabezados de manera diferente y habilita la inyección de encabezados o la omisión del control de acceso. La aceptación de encabezados CRLF está corregida en las versiones 2.1.13 y 2.2.2-alpha, pero los parches revisados no remedian claramente la condición de truncamiento NUL de URI."
      }
    ],
    "id": "CVE-2026-63385",
    "lastModified": "2026-10-26T10:10:00.140",
    "metrics": {
      "cvssMetricV40": [
        {
          "cvssData": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "availabilityRequirement": "NOT_DEFINED",
            "baseScore": 9.2,
            "baseSeverity": "CRITICAL",
            "confidentialityRequirement": "NOT_DEFINED",
            "exploitMaturity": "NOT_DEFINED",
            "integrityRequirement": "NOT_DEFINED",
            "modifiedAttackComplexity": "NOT_DEFINED",
            "modifiedAttackRequirements": "NOT_DEFINED",
            "modifiedAttackVector": "NOT_DEFINED",
            "modifiedPrivilegesRequired": "NOT_DEFINED",
            "modifiedSubAvailabilityImpact": "NOT_DEFINED",
            "modifiedSubConfidentialityImpact": "NOT_DEFINED",
            "modifiedSubIntegrityImpact": "NOT_DEFINED",
            "modifiedUserInteraction": "NOT_DEFINED",
            "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
            "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
            "modifiedVulnIntegrityImpact": "NOT_DEFINED",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "LOW",
            "subIntegrityImpact": "LOW",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:L/SI:L/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",
            "version": "4.0",
            "vulnAvailabilityImpact": "LOW",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "HIGH",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "source": "security-advisories@github.com",
          "type": "Secondary"
        }
      ],
      "ssvcV203": [
        {
          "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "ssvcData": {
            "id": "CVE-2026-63385",
            "options": [
              {
                "exploitation": "none"
              },
              {
                "automatable": "no"
              },
              {
                "technicalImpact": "partial"
              }
            ],
            "role": "CISA Coordinator",
            "timestamp": "2026-08-21T20:58:44.281954Z",
            "version": "2.0.3"
          }
        }
      ]
    },
    "published": "2026-08-20T18:16:36.543",
    "references": [
      {
        "source": "security-advisories@github.com",
        "url": "https://github.com/libevent/libevent/commit/758be0c0f69c1934ef9a84ab39e9f9e5fde2e6d0"
      },
      {
        "source": "security-advisories@github.com",
        "url": "https://github.com/libevent/libevent/commit/9170dd35e64714613e8d13b290587cfc28e258e2"
      },
      {
        "source": "security-advisories@github.com",
        "url": "https://github.com/libevent/libevent/releases/tag/release-2.1.13-stable"
      },
      {
        "source": "security-advisories@github.com",
        "url": "https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha"
      },
      {
        "source": "security-advisories@github.com",
        "url": "https://github.com/libevent/libevent/security/advisories/GHSA-jcwh-pvf2-73p2"
      }
    ],
    "sourceIdentifier": "security-advisories@github.com",
    "vulnStatus": "Awaiting Analysis",
    "weaknesses": [
      {
        "description": [
          {
            "lang": "en",
            "value": "CWE-444"
          }
        ],
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "severity": "CRITICAL",
  "source": "nvd",
  "title": "Libevent is an event notification library"
}