{ "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" }