Out-of-bounds write in libevent - #VU136938
Published: July 6, 2026
Vulnerability identifier: #VU136938
CSH Severity: Low
CVSS v4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-787
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to execute arbitrary code.
The vulnerability exists due to an out-of-bounds write in bufferevent_socket_set_conn_address_ when processing AF_UNIX accept() results for peer socket addresses. A remote attacker can connect to a vulnerable Unix domain socket with a specially crafted abstract-namespace address to execute arbitrary code.
On builds with NDEBUG, the assertion guarding the copy is disabled. Exploitation requires access to connect to the application's AF_UNIX listener, and on pthread-enabled servers the overwrite can corrupt a lock pointer that is later dereferenced inside libc.
Affected software
libevent
Remediation
Install security update from vendor's website.
libevent - update to 2.1.13