# CVE-2026-63388

## Summary

- **CVE ID:** CVE-2026-63388
- **Severity:** HIGH
- **CVSS Score:** 8.4 (CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)
- **CWE:** CWE-617, CWE-787
- **Published:** Aug 20, 2026
- **Last Modified:** Aug 21, 2026

## 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.

## Affected Products

- libevent — libevent (< 2.1.13)
- libevent — libevent (>= 2.2.0-alpha, < 2.2.2-alpha)

## References

- [CNA](https://github.com/libevent/libevent/security/advisories/GHSA-cvq5-vrvr-j338)
- [CNA](https://github.com/libevent/libevent/commit/52057cb33d0c20c0a0453fbabe6c0c96854931b9)
- [CNA](https://github.com/libevent/libevent/commit/ef38f926e9cd1f082416c6fff13587bc1f431d72)
- [CNA](https://github.com/libevent/libevent/releases/tag/release-2.1.13-stable)
- [CNA](https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.14%
- **EPSS Percentile:** 3.8

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._