CVE-2026-23405: Linux Kernel

Medium severity, CVSS 5.5. EPSS: 0.2% chance of exploitation in the next 30 days.

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.

Affected products

• Linux Linux Kernel: from 2.6.36.1, before 5.10.253 (fixed in 5.10.253); from 5.11, before 5.15.203 (fixed in 5.15.203); from 5.16, before 6.1.169 (fixed in 6.1.169); from 6.2, before 6.6.130 (fixed in 6.6.130); from 6.7, before 6.12.77 (fixed in 6.12.77); from 6.13, before 6.18.18 (fixed in 6.18.18); …

Published 2026-04-01. Last modified 2026-06-17.