{"id":"CVE-2026-63385","state":"PUBLISHED","title":"Libevent: HTTP header handling bugs create risk of access control bypass.","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.","publishedAt":"2026-08-20T17:55:36.214Z","updatedAt":"2026-08-21T21:46:26.752Z","severity":{"score":9.2,"label":"Critical","version":"4.0","vector":"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","source":"GitHub_M"},"assigner":"GitHub_M","products":["libevent libevent"],"affected":[{"vendor":"libevent","product":"libevent","versions":[{"version":">= 2.2.0-alpha, < 2.2.2-alpha","status":"affected"},{"version":"< 2.1.13","status":"affected"}]}],"references":["https://github.com/libevent/libevent/security/advisories/GHSA-jcwh-pvf2-73p2","https://github.com/libevent/libevent/commit/758be0c0f69c1934ef9a84ab39e9f9e5fde2e6d0","https://github.com/libevent/libevent/commit/9170dd35e64714613e8d13b290587cfc28e258e2","https://github.com/libevent/libevent/releases/tag/release-2.1.13-stable","https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha"],"weaknesses":["CWE-444"],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/63xxx/CVE-2026-63385.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-63385","state":"PUBLISHED","datePublished":"2026-08-20T17:55:36.214Z","dateUpdated":"2026-08-21T21:46:26.752Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-07-16T17:39:30.171Z"},"containers":{"cna":{"title":"Libevent: HTTP header handling bugs create risk of access control bypass.","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."}],"affected":[{"vendor":"libevent","product":"libevent","versions":[{"version":">= 2.2.0-alpha, < 2.2.2-alpha","status":"affected"},{"version":"< 2.1.13","status":"affected"}]}],"references":[{"url":"https://github.com/libevent/libevent/security/advisories/GHSA-jcwh-pvf2-73p2","name":"https://github.com/libevent/libevent/security/advisories/GHSA-jcwh-pvf2-73p2","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/libevent/libevent/commit/758be0c0f69c1934ef9a84ab39e9f9e5fde2e6d0","name":"https://github.com/libevent/libevent/commit/758be0c0f69c1934ef9a84ab39e9f9e5fde2e6d0","tags":["x_refsource_MISC"]},{"url":"https://github.com/libevent/libevent/commit/9170dd35e64714613e8d13b290587cfc28e258e2","name":"https://github.com/libevent/libevent/commit/9170dd35e64714613e8d13b290587cfc28e258e2","tags":["x_refsource_MISC"]},{"url":"https://github.com/libevent/libevent/releases/tag/release-2.1.13-stable","name":"https://github.com/libevent/libevent/releases/tag/release-2.1.13-stable","tags":["x_refsource_MISC"]},{"url":"https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha","name":"https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH","vulnAvailabilityImpact":"LOW","subConfidentialityImpact":"LOW","subIntegrityImpact":"LOW","subAvailabilityImpact":"NONE","baseScore":9.2,"baseSeverity":"CRITICAL","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","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-444","lang":"en","description":"CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-08-20T17:55:36.214Z"},"source":{"advisory":"GHSA-jcwh-pvf2-73p2","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-21T20:58:44.281954Z","id":"CVE-2026-63385","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-21T21:46:26.752Z"}}]}}}