CVE-2026-90231

Name	CVE-2026-90231
Description	In the Linux kernel, the following vulnerability has been resolved: apparmor: fix unconfined user namespace restriction forced stack If a task is already confined by a stack the unprivileged transition restriction on unconfined is not correctly, applied. This results in an escape if two transitions through an unconfined profile can be executed. Fix this by pushing the check into the per profile label build. The check will always be done against unconfined and result in a stack of just the unconfined component when necessary.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
linux (PTS)	bookworm	6.1.176-1	fixed
	bookworm (security)	6.1.187-1	fixed
	trixie	6.12.107-1	vulnerable
	trixie (security)	6.12.111-1	vulnerable
	forky	7.2.8-1	fixed
	sid	7.2.9-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
linux	source	bookworm	(not affected)
linux	source	(unstable)	7.2.6-1

[bookworm] - linux <not-affected> (Vulnerable code not present)
https://git.kernel.org/linus/08c2f7c8d4b1434cfae006f3daf4d1bce330b57b (7.3-rc1)