Vulnerability Description
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.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://github.com/libevent/libevent/commit/52057cb33d0c20c0a0453fbabe6c0c968549
- https://github.com/libevent/libevent/commit/ef38f926e9cd1f082416c6fff13587bc1f43
- https://github.com/libevent/libevent/releases/tag/release-2.1.13-stable
- https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha
- https://github.com/libevent/libevent/security/advisories/GHSA-cvq5-vrvr-j338
FAQ
What is CVE-2026-63388?
CVE-2026-63388 is a vulnerability with a CVSS score of 8.4 (HIGH). 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-supp...
How severe is CVE-2026-63388?
CVE-2026-63388 has been rated HIGH with a CVSS base score of 8.4/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-63388?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.