{"id":"CVE-2026-63381","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 has a use-after-free in buffer.c when evbuffer_add_buffer_reference processes an output buffer whose out_total_len is zero. evbuffer_free_all_chains fre…","severity":"medium","cwe":["CWE-908","CWE-825"],"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-2026-63381","references":[{"url":"https://github.com/libevent/libevent/commit/5cb95ba2f804f8aff46f88d58391c71e1251cd1c","label":"security-advisories@github.com"},{"url":"https://github.com/libevent/libevent/commit/9db091b04f569be3a700fa9860ef02f90b830af9","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-c2pj-cg4r-88c8","label":"security-advisories@github.com"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63381.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-63381"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2520657"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-63381"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63381"},{"url":"https://access.redhat.com/errata/RHSA-2026:67909"},{"url":"https://access.redhat.com/errata/RHSA-2026:67910"},{"url":"https://access.redhat.com/errata/RHSA-2026:60853"},{"url":"https://access.redhat.com/errata/RHSA-2026:71603"}],"tags":["nvd","csaf","vex","red-hat"],"epss":0.0016,"epssPercentile":0.04452,"ingestedAt":"2026-09-09T21:22:45.544Z","vendor":"Red Hat","product":"Red Hat Enterprise Linux AppStream (v. 9)","affected":["enterprise_linux 6","enterprise_linux 7","enterprise_linux 8","openshift_container_platform 4","enterprise_linux_appstream_v_10","enterprise_linux_appstream_v_9","enterprise_linux_baseos_v_10","enterprise_linux_baseos_v_9","hardened_images"],"patched":["enterprise_linux_appstream_v_10","enterprise_linux_appstream_v_9","enterprise_linux_baseos_v_10","enterprise_linux_baseos_v_9","hardened_images"],"cvss":6.6,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H","cvssSource":"vendor","slug":"CVE-2026-63381","body":"## Overview\n\nLibevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has a use-after-free in buffer.c when evbuffer_add_buffer_reference processes an output buffer whose out_total_len is zero. evbuffer_free_all_chains frees the initial empty chain without resetting outbuf->first, outbuf->last, or outbuf->last_with_datap, and APPEND_CHAIN_MULTICAST subsequently dereferences the dangling chain pointer. A caller that can drive this buffer state can cause memory corruption or a process crash. 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-2026:67909** · 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-2026:67910** · 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)\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** · Moderate · affected: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat OpenShift Container Platform 4 · updated 2026-09-24 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63381.json)\n- **RHSA-2026:71603** · Red Hat · fixed in: Red Hat Update Infrastructure 5 · released 2026-09-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:71603)","depth":"sunlit","depthScore":36,"depthScoreParts":{"impact":36.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":206409,"id":"CVE-2026-63381","ts":1789663225088,"field":"cvss","old":null,"new":"6.6"},{"seq":206408,"id":"CVE-2026-63381","ts":1789663225088,"field":"severity","old":"none","new":"medium"}]}