CVE-2026-63388
Publication date 20 August 2026
Last updated 30 September 2026
Ubuntu priority
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.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| libevent | 26.04 LTS resolute |
Fixed 2.1.12-stable-10ubuntu0.2
|
| 24.04 LTS noble |
Fixed 2.1.12-stable-9ubuntu2.2
|
|
| 22.04 LTS jammy |
Fixed 2.1.12-stable-1ubuntu0.2
|
|
| 20.04 LTS focal |
Fixed 2.1.11-stable-1ubuntu0.1~esm2
|
|
| 18.04 LTS bionic |
Fixed 2.1.8-stable-4ubuntu0.1~esm2
|
|
| 16.04 LTS xenial |
Not affected
|
|
| 14.04 LTS trusty |
Not affected
|
Get expanded security coverage with Ubuntu Pro
Reduce your average CVE exposure time from 98 days to 1 day with expanded CVE patching, ten-years security maintenance and optional support for the full stack of open-source applications. Free for personal use.
Get Ubuntu Pro 30-day free trialSeverity score breakdown
CVSS version: CVSS v3.0
Base score
8.4 · High
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
Related Ubuntu Security Notices (USN)
- USN-8840-1
- libevent vulnerabilities
- 28 September 2026