CVE-2026-63379

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{"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."}, {"lang": "es", "value": "Libevent es una biblioteca de notificaci\u00f3n de eventos. Antes de 2.1.13 y 2.2.2-alpha, libevent procesa los tr\u00e1ileres HTTP segmentados en http.c a trav\u00e9s de evhttp_read_trailer y los fusiona en los encabezados de solicitud. La correcci\u00f3n introduce evhttp_parse_headers_impl_ y una lista temporal de encabezados de tr\u00e1iler. Un atacante remoto no autenticado puede colocar campos sensibles a la seguridad en los tr\u00e1ileres de modo que un proxy ascendente y la aplicaci\u00f3n libevent interpreten encabezados efectivos diferentes, lo que permite el contrabando de encabezados, la omisi\u00f3n de autorizaci\u00f3n, la suplantaci\u00f3n de encabezados de proxy o el envenenamiento de cach\u00e9. La correcci\u00f3n analiza los tr\u00e1ileres en una lista temporal de encabezados y los descarta en lugar de fusionarlos en req -> input_headers. Este problema est\u00e1 corregido en las versiones 2.1.13 y 2.2.2-alpha."}], "id": "CVE-2026-63379", "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": 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"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-63379", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-08-25T15:14:11.010475Z", "version": "2.0.3"}}]}, "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": "Awaiting Analysis", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-444"}], "source": "security-advisories@github.com", "type": "Secondary"}]}

{"bugzilla": {"description": "libevent: Libevent: HTTP header smuggling allows authorization bypass or cache poisoning", "id": "2520667", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2520667"}, "csaw": false, "cvss3": {"cvss3_base_score": "6.5", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N", "status": "draft"}, "cwe": "CWE-444", "details": ["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.", "A flaw was found in Libevent, an event notification library. An unauthenticated remote attacker can exploit a vulnerability where chunked HTTP (Hypertext Transfer Protocol) trailers are incorrectly merged into request headers. This allows the attacker to place security-sensitive fields in trailers, causing an upstream proxy and the Libevent application to interpret different effective headers. This can lead to header smuggling, authorization bypass, proxy-header spoofing, or cache poisoning."], "name": "CVE-2026-63379", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "libevent", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "libevent", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "libevent2", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Fix deferred", "package_name": "libevent", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "libevent", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "libevent", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:hummingbird:1", "fix_state": "Affected", "package_name": "libevent", "product_name": "Red Hat Hardened Images"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Fix deferred", "package_name": "openshift/ose-rhel-coreos-8", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Fix deferred", "package_name": "openshift/ose-rhel-coreos-9", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-08-20T17:55:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-63379\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-63379\nhttps://github.com/libevent/libevent/commit/87e8e44fa774e9677b089b1a5114ee68aefa1636\nhttps://github.com/libevent/libevent/commit/b847071141b3827900d536594ec9045eb0a4c485\nhttps://github.com/libevent/libevent/releases/tag/release-2.1.13-stable\nhttps://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha\nhttps://github.com/libevent/libevent/security/advisories/GHSA-2gmv-p5m7-98p6"], "threat_severity": "Moderate"}

{"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"]}