{"id":"CVE-2026-63383","state":"PUBLISHED","title":"Libevent: decode_tag_internal() can lead to out-of-bounds read","description":"Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent can read beyond a contiguous evbuffer region in event_tagging.c when decode_tag_internal requests at most five bytes from evbuffer_pullup but iterates using the full logical buffer length. A fragmented evbuffer containing a six-byte malformed tag can therefore advance past the pullup window and trigger an out-of-bounds read, which can crash a process that decodes attacker-controlled tagged RPC data. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.","publishedAt":"2026-08-20T17:48:24.568Z","updatedAt":"2026-08-20T18:41:23.897Z","severity":{"score":8.7,"label":"High","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/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-fj29-64w6-73h6","https://github.com/libevent/libevent/commit/91ed8745eebabdd27592a83d350338a8c4626321","https://github.com/libevent/libevent/commit/e1f9e21887c6b104e206a718385ba3ffc75180cb","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-125"],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/63xxx/CVE-2026-63383.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-63383","state":"PUBLISHED","datePublished":"2026-08-20T17:48:24.568Z","dateUpdated":"2026-08-20T18:41:23.897Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-07-16T17:39:30.171Z"},"containers":{"cna":{"title":"Libevent: decode_tag_internal() can lead to out-of-bounds read","descriptions":[{"lang":"en","value":"Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent can read beyond a contiguous evbuffer region in event_tagging.c when decode_tag_internal requests at most five bytes from evbuffer_pullup but iterates using the full logical buffer length. A fragmented evbuffer containing a six-byte malformed tag can therefore advance past the pullup window and trigger an out-of-bounds read, which can crash a process that decodes attacker-controlled tagged RPC data. This issue is fixed in versions 2.1.13 and 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"}]}],"references":[{"url":"https://github.com/libevent/libevent/security/advisories/GHSA-fj29-64w6-73h6","name":"https://github.com/libevent/libevent/security/advisories/GHSA-fj29-64w6-73h6","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/libevent/libevent/commit/91ed8745eebabdd27592a83d350338a8c4626321","name":"https://github.com/libevent/libevent/commit/91ed8745eebabdd27592a83d350338a8c4626321","tags":["x_refsource_MISC"]},{"url":"https://github.com/libevent/libevent/commit/e1f9e21887c6b104e206a718385ba3ffc75180cb","name":"https://github.com/libevent/libevent/commit/e1f9e21887c6b104e206a718385ba3ffc75180cb","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":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":8.7,"baseSeverity":"HIGH","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-125","lang":"en","description":"CWE-125: Out-of-bounds Read","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-08-20T17:48:24.568Z"},"source":{"advisory":"GHSA-fj29-64w6-73h6","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/libevent/libevent/security/advisories/GHSA-fj29-64w6-73h6","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-20T18:37:55.514994Z","id":"CVE-2026-63383","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-20T18:41:23.897Z"}}]}}}