{"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"}