{"id":"CVE-2026-63383","title":"Libevent is an event notification library","summary":"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 u…","severity":"high","cvss":8.7,"cvssVector":"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","cwe":["CWE-125"],"vendor":"libevent","product":"libevent","affected":["libevent >= 2.2.0-alpha, < 2.2.2-alpha","libevent < 2.1.13"],"published":"2026-08-20","updated":"2026-09-09","sourceUpdated":"2026-09-09T21:19:49.197","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-63383","references":[{"url":"https://github.com/libevent/libevent/commit/91ed8745eebabdd27592a83d350338a8c4626321","label":"security-advisories@github.com"},{"url":"https://github.com/libevent/libevent/commit/e1f9e21887c6b104e206a718385ba3ffc75180cb","label":"security-advisories@github.com"},{"url":"https://github.com/libevent/libevent/releases/tag/release-2.1.13-stable","label":"security-advisories@github.com"},{"url":"https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha","label":"security-advisories@github.com"},{"url":"https://github.com/libevent/libevent/security/advisories/GHSA-fj29-64w6-73h6","label":"security-advisories@github.com"},{"url":"https://github.com/libevent/libevent/security/advisories/GHSA-fj29-64w6-73h6","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63383.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-63383"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2520654"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-63383"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63383"},{"url":"https://access.redhat.com/errata/RHSA-2026:60853"},{"url":"https://access.redhat.com/errata/RHSA-2026:67909"},{"url":"https://access.redhat.com/errata/RHSA-2026:67908"},{"url":"https://access.redhat.com/errata/RHSA-2026:67910"}],"tags":["nvd","cve.org","exploit-available","csaf","vex","red-hat"],"exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"yes","technicalImpact":"partial","timestamp":"2026-08-20T18:37:55.514994Z"},"cvssSource":"cna","ingestedAt":"2026-09-14T04:35:15.069Z","epss":0.00384,"epssPercentile":0.32346,"patched":["hardened_images"],"scores":{"cna":8.7,"vendor":7.5},"slug":"CVE-2026-63383","body":"## Overview\n\nLibevent 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **RHSA-2026:60853** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-08-29 · [advisory](https://access.redhat.com/errata/RHSA-2026:60853)\n- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · updated 2026-09-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63383.json)\n- **RHSA-2026:67909** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10) · released 2026-09-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:67909)\n- **RHSA-2026:67908** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 8), Red Hat Enterprise Linux BaseOS (v. 8) · released 2026-09-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:67908)\n- **RHSA-2026:67910** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9) · released 2026-09-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:67910)","depth":"midnight","depthScore":60,"depthScoreParts":{"impact":47.8,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[{"seq":109657,"id":"CVE-2026-63383","ts":1789183733092,"field":"cvss","old":null,"new":"7.5"},{"seq":109656,"id":"CVE-2026-63383","ts":1789183733092,"field":"severity","old":"none","new":"high"}]}