Executive brief
A flaw has been identified in the Ubuntu Linux kernel's AppArmor security component, which is responsible for restricting programs' capabilities to protect the system. An attacker with basic access to the system can trigger a specific error that causes the entire operating system to crash or freeze (deadlock). This results in a complete loss of availability for the affected server or workstation, potentially disrupting business operations.
Technical details
The vulnerability is caused by a 'sleep while holding a spinlock' condition within the AppArmor SAUCE patches in the Ubuntu Linux kernel. Specifically, the notification handling code incorrectly attempts to perform a sleeping operation while holding a non-sleepable spinlock, violating kernel locking primitives. An unprivileged local user can trigger this code path to induce a kernel panic or a deadlock (CWE-833). The issue affects Ubuntu-specific kernel versions 6.8, 6.17, and 7.0. A fix has been committed to the Ubuntu kernel source tree.
Affected products
- Ubuntu Linux Kernel 6.8, 6.17, 7.0
Timeline
- 2026-05-28: disclosed
- 2026-05-28: advisory