{"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": "2026-08-20T17:55:00.789Z"}, "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"}}}}

{}

{"affected": [{"affectedData": [{"product": "libevent", "vendor": "libevent", "versions": [{"status": "affected", "version": "< 2.1.13"}, {"status": "affected", "version": ">= 2.2.0-alpha, < 2.2.2-alpha"}]}], "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 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."}], "id": "CVE-2026-63379", "lastModified": "2026-08-20T18:16:35.200", "metrics": {"cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 6.3, "baseSeverity": "MEDIUM", "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": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "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/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": "NONE", "vulnConfidentialityImpact": "LOW", "vulnIntegrityImpact": "LOW", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-08-20T18:16:35.200", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/libevent/libevent/commit/87e8e44fa774e9677b089b1a5114ee68aefa1636"}, {"source": "security-advisories@github.com", "url": "https://github.com/libevent/libevent/commit/b847071141b3827900d536594ec9045eb0a4c485"}, {"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-2gmv-p5m7-98p6"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-444"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,2.1.13)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[2.2.0-alpha,2.2.2-alpha)"}}], "enrichment": {"confidence": 81.0, "confidence_source": "matching", "scores": [{"score": 81.0, "source": "matching"}]}, "original": {"product": "libevent", "source": "cna", "vendor": "libevent"}, "product": "libevent", "vendor": "libevent_project"}], "created": "2026-08-21T02:15:04.424428+00:00", "updated": "2026-08-21T13:01:03.079938+00:00", "vendors": ["libevent_project", "libevent_project$PRODUCT$libevent"]}