Qualys has sent out a somewhat breathless advisory describing a number of vulnerabilities in the AppArmor security module, which is used in a number of Debian-based distributions (among others).

This "CrackArmor" advisory exposes a confused-deputy flaw allowing unprivileged users to manipulate security profiles via pseudo-files, bypass user-namespace restrictions, and execute arbitrary code within the kernel. These flaws facilitate local privilege escalation to root through complex interactions with tools like Sudo and Postfix, alongside denial-of-service attacks via stack exhaustion and Kernel Address Space Layout Randomization (KASLR) bypasses via out-of-bounds reads.