CVE-2026-63388
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 heap out-of-bounds write in bufferevent_sock.c when bufferevent_socket_set_conn_address_ copies a kernel-supplied AF_UNIX peer address into bufferevent_private.conn_address. Release builds compiled with NDEBUG disable the EVUTIL_ASSERT length guard, and the evhttp accept path can pass a 110-byte sockaddr from accept() into the 28-byte field. An unauthenticated local peer able to connect to an AF_UNIX listener can overwrite the adjacent dns_request pointer and heap data, causing memory corruption with confidentiality, integrity, and availability impact. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.
Risk Scores
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| libevent | libevent | < 2.1.13, >= 2.2.0-alpha, < 2.2.2-alpha |
| libevent | libevent | < 2.1.13, >= 2.2.0-alpha, < 2.2.2-alpha, < 2.1.13 |
Timeline
- Aug 20, 2026 CVE Published
- Aug 20, 2026 CVE Updated
- Aug 22, 2026 Coalition ESS Score
- Aug 24, 2026 EPSS Score
- Sep 3, 2026 Security Advisory
- Sep 9, 2026 EPSS Score
- Sep 20, 2026 Distribution Patch
- Sep 20, 2026 Distribution Patch
- Sep 20, 2026 Distribution Patch
References
- https://github.com/libevent/libevent/security/advisories/GHSA-cvq5-vrvr-j338 x_refsource_CONFIRM
- https://github.com/libevent/libevent/commit/52057cb33d0c20c0a0453fbabe6c0c96854931b9 x_refsource_MISC
- https://github.com/libevent/libevent/commit/ef38f926e9cd1f082416c6fff13587bc1f431d72 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