CVE-2026-90231
High
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.
SeverityHigh
CVSS8.4
Exploit probability5. percentile0.2%
Product
Linux
PublishedSep 17, 2026
First seenSep 17, 2026
How to fix
Update
- Linux Linuxfdd341654471cae4fbd9635d32b848cd0c8bc437, 7d1099b86356df81c379159bfb8a598aaf83ce81, 7da0bdf0610f6d35bbb061536a47fc41646306f0, 08c2f7c8d4b1434cfae006f3daf4d1bce330b57b or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Linux Linux | 2d9da9b188b8cd3b579d7ef5ba5d334be9dd38fc ≤ v < fdd341654471cae4fbd9635d32b848cd0c8bc437, 2d9da9b188b8cd3b579d7ef5ba5d334be9dd38fc ≤ v < 7d1099b86356df81c379159bfb8a598aaf83ce81, 2d9da9b188b8cd3b579d7ef5ba5d334be9dd38fc ≤ v < 7da0bdf0610f6d35bbb061536a47fc41646306f0, 2d9da9b188b8cd3b579d7ef5ba5d334be9dd38fc ≤ v < 08c2f7c8d4b1434cfae006f3daf4d1bce330b57b, 6.7 | fdd341654471cae4fbd9635d32b848cd0c8bc437, 7d1099b86356df81c379159bfb8a598aaf83ce81, 7da0bdf0610f6d35bbb061536a47fc41646306f0, 08c2f7c8d4b1434cfae006f3daf4d1bce330b57b |
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