{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-63379","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-07-16T17:39:30.170Z","datePublished":"2026-08-20T17:55:00.789Z","dateUpdated":"2026-08-25T15:14:26.228Z"},"containers":{"cna":{"title":"Libevent: HTTP Header smuggling","problemTypes":[{"descriptions":[{"cweId":"CWE-444","lang":"en","description":"CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')","type":"CWE"}]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"LOW","vulnIntegrityImpact":"LOW","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":6.3,"baseSeverity":"MEDIUM","vectorString":"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","version":"4.0"}}],"references":[{"name":"https://github.com/libevent/libevent/security/advisories/GHSA-2gmv-p5m7-98p6","tags":["x_refsource_CONFIRM"],"url":"https://github.com/libevent/libevent/security/advisories/GHSA-2gmv-p5m7-98p6"},{"name":"https://github.com/libevent/libevent/commit/87e8e44fa774e9677b089b1a5114ee68aefa1636","tags":["x_refsource_MISC"],"url":"https://github.com/libevent/libevent/commit/87e8e44fa774e9677b089b1a5114ee68aefa1636"},{"name":"https://github.com/libevent/libevent/commit/b847071141b3827900d536594ec9045eb0a4c485","tags":["x_refsource_MISC"],"url":"https://github.com/libevent/libevent/commit/b847071141b3827900d536594ec9045eb0a4c485"},{"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-2.1.13-stable"},{"name":"https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha","tags":["x_refsource_MISC"],"url":"https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha"}],"affected":[{"vendor":"libevent","product":"libevent","versions":[{"version":"< 2.1.13","status":"affected"},{"version":">= 2.2.0-alpha, < 2.2.2-alpha","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-08-20T17:55:00.789Z"},"descriptions":[{"lang":"en","value":"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->input_headers. This issue is fixed in versions 2.1.13 and 2.2.2-alpha."}],"source":{"advisory":"GHSA-2gmv-p5m7-98p6","discovery":"UNKNOWN"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-25T15:14:11.010475Z","id":"CVE-2026-63379","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-08-25T15:14:26.228Z"}}]}}