{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-63382", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-07-16T17:39:30.171Z", "datePublished": "2026-08-20T17:51:15.156Z", "dateUpdated": "2026-08-20T19:33:50.217Z"}, "containers": {"cna": {"title": "libevent evhttp: Multiple HTTP Parser Bugs Enable Request 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": "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"}}], "references": [{"name": "https://github.com/libevent/libevent/security/advisories/GHSA-q39v-w2g7-gr8j", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/libevent/libevent/security/advisories/GHSA-q39v-w2g7-gr8j"}, {"name": "https://github.com/libevent/libevent/commit/10abb34b8dc3e1184de315dd261ce4b77563cda6", "tags": ["x_refsource_MISC"], "url": "https://github.com/libevent/libevent/commit/10abb34b8dc3e1184de315dd261ce4b77563cda6"}, {"name": "https://github.com/libevent/libevent/commit/5119ceb00557bf007f9065709e852686f3c0bb6e", "tags": ["x_refsource_MISC"], "url": "https://github.com/libevent/libevent/commit/5119ceb00557bf007f9065709e852686f3c0bb6e"}, {"name": "https://github.com/libevent/libevent/commit/83ba67373032334559b82409db035dd8c3cc1660", "tags": ["x_refsource_MISC"], "url": "https://github.com/libevent/libevent/commit/83ba67373032334559b82409db035dd8c3cc1660"}, {"name": "https://github.com/libevent/libevent/commit/ac38703b2d312200c4f967f02936af0118d384a0", "tags": ["x_refsource_MISC"], "url": "https://github.com/libevent/libevent/commit/ac38703b2d312200c4f967f02936af0118d384a0"}, {"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": ">= 2.2.0-alpha, < 2.2.2-alpha", "status": "affected"}, {"version": "< 2.1.13", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-08-20T17:51:15.156Z"}, "descriptions": [{"lang": "en", "value": "Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, the libevent evhttp parser in http.c inconsistently handles duplicate Transfer-Encoding headers, comma-separated Transfer-Encoding values, and bare line feeds in chunked framing. evhttp_find_header can select only the first header, evhttp_check_transfer_encoding_ was absent so the previous whole-string comparison fails to recognize valid lists ending in chunked, and evhttp_handle_chunked_read uses EVBUFFER_EOL_CRLF rather than EVBUFFER_EOL_CRLF_STRICT, accepting bare LF chunk terminators. When libevent is deployed behind a proxy that frames the same request differently, an unauthenticated remote attacker can desynchronize request boundaries and smuggle a second request, potentially bypassing access controls or poisoning caches. This issue is fixed in versions 2.1.13 and 2.2.2-alpha."}], "source": {"advisory": "GHSA-q39v-w2g7-gr8j", "discovery": "UNKNOWN"}}, "adp": [{"references": [{"url": "https://github.com/libevent/libevent/security/advisories/GHSA-q39v-w2g7-gr8j", "tags": ["exploit"]}], "metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-08-20T19:33:43.608585Z", "id": "CVE-2026-63382", "options": [{"Exploitation": "poc"}, {"Automatable": "yes"}, {"Technical Impact": "total"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-08-20T19:33:50.217Z"}}]}}

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{"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, the libevent evhttp parser in http.c inconsistently handles duplicate Transfer-Encoding headers, comma-separated Transfer-Encoding values, and bare line feeds in chunked framing. evhttp_find_header can select only the first header, evhttp_check_transfer_encoding_ was absent so the previous whole-string comparison fails to recognize valid lists ending in chunked, and evhttp_handle_chunked_read uses EVBUFFER_EOL_CRLF rather than EVBUFFER_EOL_CRLF_STRICT, accepting bare LF chunk terminators. When libevent is deployed behind a proxy that frames the same request differently, an unauthenticated remote attacker can desynchronize request boundaries and smuggle a second request, potentially bypassing access controls or poisoning caches. This issue is fixed in versions 2.1.13 and 2.2.2-alpha."}], "id": "CVE-2026-63382", "lastModified": "2026-08-20T18:16:35.700", "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"}]}, "published": "2026-08-20T18:16:35.700", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/libevent/libevent/commit/10abb34b8dc3e1184de315dd261ce4b77563cda6"}, {"source": "security-advisories@github.com", "url": "https://github.com/libevent/libevent/commit/5119ceb00557bf007f9065709e852686f3c0bb6e"}, {"source": "security-advisories@github.com", "url": "https://github.com/libevent/libevent/commit/83ba67373032334559b82409db035dd8c3cc1660"}, {"source": "security-advisories@github.com", "url": "https://github.com/libevent/libevent/commit/ac38703b2d312200c4f967f02936af0118d384a0"}, {"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-q39v-w2g7-gr8j"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-444"}], "source": "security-advisories@github.com", "type": "Primary"}]}

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