CVE-2026-63381
Publication date 21 August 2026
Last updated 2 September 2026
Ubuntu priority
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.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| libevent | 26.04 LTS resolute |
Fixed 2.1.12-stable-10ubuntu0.1
|
| 24.04 LTS noble |
Fixed 2.1.12-stable-9ubuntu2.1
|
|
| 22.04 LTS jammy |
Fixed 2.1.12-stable-1ubuntu0.1
|
|
| 20.04 LTS focal |
Fixed 2.1.11-stable-1ubuntu0.1~esm1
|
|
| 18.04 LTS bionic |
Fixed 2.1.8-stable-4ubuntu0.1~esm1
|
|
| 16.04 LTS xenial |
Not affected
|
|
| 14.04 LTS trusty |
Not affected
|
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CVSS version: CVSS v4.0
Base score
5.8 · Medium
Vector: 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
References
Related Ubuntu Security Notices (USN)
- USN-8710-1
- libevent vulnerabilities
- 1 September 2026