High [CVE-2026-63388] Arbitrary code execution via heap out-of-bounds write in AF_UNIX handling
This high-severity Red Hat Linux advisory covers CVE-2026-63388 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7.
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Summary
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. A flaw was found in Libevent.
A heap out-of-bounds write vulnerability in the `bufferevent_socket_set_conn_address_` function allows an unauthenticated local peer to achieve arbitrary code execution. By connecting to an AF_UNIX listener, an attacker can overwrite critical heap data, leading to memory corruption and potentially full control over the affected system.
Red Hat severity: Important — CVSS 8.4 (CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H). Weakness: CWE-787.
Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9; Red Hat Hardened Images; Red Hat OpenShift Container Platform 4.
- < 2.1.13
- < 2.2.2-alpha
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
- 2.1.13
- 2.2.2
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Mitigation
Upgrade to a fixed release: 2.1.13, 2.2.2. That is the remediation for this advisory.
The vendor advisory may list additional interim mitigations or workarounds not captured here — review it before change work.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
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