VDB
CVE-2026-63381
CVE-2026-63381
PUBLISHED
CVSS 5.8 MEDIUM
Reported by GitHub_M · Published August 20, 2026
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 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.
Risk Scores
CVSS 4.0
5.8
CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| libevent | libevent | >= 2.2.0-alpha, < 2.2.2-alpha, < 2.1.13 |
| libevent | libevent | >= 2.2.0-alpha, < 2.2.2-alpha, < 2.1.13, >= 2.2.0-alpha, < 2.2.2-alpha |
Timeline
- Aug 20, 2026 CVE Published
- Aug 22, 2026 Coalition ESS Score
- Aug 24, 2026 EPSS Score
- Sep 3, 2026 Security Advisory
- Sep 9, 2026 CVE Updated
- Sep 20, 2026 Distribution Patch
- Sep 20, 2026 Distribution Patch
References
- https://github.com/libevent/libevent/security/advisories/GHSA-c2pj-cg4r-88c8 x_refsource_CONFIRM
- https://github.com/libevent/libevent/commit/5cb95ba2f804f8aff46f88d58391c71e1251cd1c x_refsource_MISC
- https://github.com/libevent/libevent/commit/9db091b04f569be3a700fa9860ef02f90b830af9 x_refsource_MISC
- https://github.com/libevent/libevent/releases/tag/release-2.1.13-stable x_refsource_MISC
- https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha x_refsource_MISC