CVE-2026-63381
Libevent: Dangling Pointer in `evbuffer_add_buffer_reference`
- State
- Published
- Severity
- 5.8 Medium
- Published
- Aug 20, 2026
- Updated
- Aug 21, 2026
- Reserved
- Jul 16, 2026
Description
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 5.8 Medium | 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 | GitHub_M |
Weaknesses
- CWE-908 Use of Uninitialized Resource
Affected Products
| Product | Versions |
|---|---|
libeventlibevent |
|
References
- https://github.com/libevent/libevent/security/advisories/GHSA-c2pj-cg4r-88c8
- https://github.com/libevent/libevent/commit/5cb95ba2f804f8aff46f88d58391c71e1251cd1c
- https://github.com/libevent/libevent/commit/9db091b04f569be3a700fa9860ef02f90b830af9
- https://github.com/libevent/libevent/releases/tag/release-2.1.13-stable
- https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha
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