CVE-2026-90179

Name of the Vulnerable Software and Affected Versions Linux kernel versions 6.18.44 through 7.2-rc7

Description A deadlock occurs in AppArmor when using the change hat() function while in complain mode. The issue arises when a requested hat does not exist, triggering the creation of a new learning profile via the aa new learning profile() function. Because change hat() already holds the lock to search the hat list, and aa new learning profile() attempts to acquire the same lock to add the new profile to the list, the system enters a deadlock state. This results in the executable hanging and becoming unkillable. Additionally, the issue involves reference count leaks in change hat() and a potential Use-After-Free (UAF) condition during profile lookup when navigating namespace trees.

Recommendations Update the Linux kernel to a version where the locking mechanism in aa new learning profile() has been refactored to avoid recursive locking during build change hat() calls.