CVE-2026-63381
Published:August 20, 2026
Updated:September 02, 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.
Affected Packages
https://github.com/libevent/libevent.git (GITHUB):
Affected version(s) >=release-1.1b <release-2.1.13-stableFix Suggestion:
Update to version release-2.1.13-stablehttps://github.com/libevent/libevent.git (GITHUB):
Affected version(s) =release-2.2.1-alpha <release-2.2.2-alphaFix Suggestion:
Update to version release-2.2.2-alphaRelated Resources (7)
Do you need more information?
Contact UsCVSS v4
Base Score:
5.8
Attack Vector
LOCAL
Attack Complexity
LOW
Attack Requirements
PRESENT
Privileges Required
LOW
User Interaction
NONE
Vulnerable System Confidentiality
LOW
Vulnerable System Integrity
LOW
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
6.6
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
HIGH
Weakness Type (CWE)
Use of Uninitialized Resource
EPSS
Base Score:
0.12