CVE-2026-23405

Name	CVE-2026-23405
Description	In the Linux kernel, the following vulnerability has been resolved: apparmor: fix: limit the number of levels of policy namespaces Currently the number of policy namespaces is not bounded relying on the user namespace limit. However policy namespaces aren't strictly tied to user namespaces and it is possible to create them and nest them arbitrarily deep which can be used to exhaust system resource. Hard cap policy namespaces to the same depth as user namespaces.
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)	bullseye	5.10.223-1	vulnerable
	bullseye (security)	5.10.251-1	fixed
	bookworm	6.1.159-1	vulnerable
	bookworm (security)	6.1.164-1	fixed
	trixie	6.12.73-1	vulnerable
	trixie (security)	6.12.74-2	fixed
	forky	6.19.11-1	fixed
	sid	6.19.13-1	fixed

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

Package	Type	Release	Fixed Version
linux	source	bullseye	5.10.251-1
linux	source	bookworm	6.1.164-1
linux	source	trixie	6.12.74-2
linux	source	(unstable)	6.19.6-2

https://git.kernel.org/linus/306039414932c80f8420695a24d4fe10c84ccfb2 (7.0-rc4)
https://www.qualys.com/2026/03/10/crack-armor.txt