A recently disclosed vulnerability (CVE-2026-80521) affects the Linux kernel AF_UNIX socket subsystem and may allow an attacker to escape a container and obtain root privileges on the host system.
Severity level:
CVSS Score: 7.8/High
Description:
CVE-2026-80521 is a use-after-free vulnerability in the Linux kernel's AF_UNIX socket subsystem caused by a race condition in the garbage collection mechanism used to manage file descriptors passed through SCM_RIGHTS messages. An attacker with code execution inside a container can exploit the flaw to corrupt kernel memory, escape container isolation, and gain root privileges on the underlying host.
Affected Versions:
- Ubuntu 26.04 LTS.
- Ubuntu 24.04 LTS.
- Ubuntu 22.04 LTS.
- Red Hat Enterprise Linux 10.
- Debian 12,13,14.
- Upstream Linux Kernel (All versions prior to official patch committed on Aug 6, 2026).
Impact:
Successful exploitation may allow attackers to obtain root privileges on the host operating system.
Resolution:
Apply vendor-provided kernel updates as soon as they become available. Monitor Ubuntu and vendor security advisories for package availability.
Reference:
https://nvd.nist.gov/vuln/detail/cve-2026-80521
https://access.redhat.com/security/cve/cve-2026-80521
https://ubuntu.com/security/CVE-2026-80521
https://thehackernews.com/2026/09/exploit-released-for-unpatched-ubuntu.html
https://www.suse.com/security/cve/CVE-2026-80521.html
UIT Information Security