Exploit Released for Unpatched Ubuntu Linux Container Escape Flaw

DepthFirst published an exploit for a use-after-free in the Linux kernel's AF_UNIX socket subsystem (CVE-2026-80521, CVSS 7.8) that allows container escape and host root access. The flaw was fixed upstream on August 6, but Ubuntu has not shipped the patch for its 26.04, 24.04, or 22.04 LTS releases.

• CVE-2026-80521 carries a CVSS score of 7.8
• Exploit grants root on the host via container escape
• Upstream patch landed August 6, Ubuntu has not shipped it
• Ubuntu 26.04, 24.04 and 22.04 LTS are affected