What’s Vulnerable › Vulnerabilities

CVE-2026-90231: apparmor: fix unconfined user namespace restriction forced stack

• Severity: high (CVSS 8.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-17 · updated 2026-10-21

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.

Affected products

• Linux kernel: 6.7 — fixed in 7.3

How to fix

Upgrade to a fixed version: Linux kernel 7.3. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/08c2f7c8d4b1434cfae006f3daf4d1bce330b57b
• https://git.kernel.org/stable/c/7d1099b86356df81c379159bfb8a598aaf83ce81
• https://git.kernel.org/stable/c/7da0bdf0610f6d35bbb061536a47fc41646306f0
• https://git.kernel.org/stable/c/fdd341654471cae4fbd9635d32b848cd0c8bc437

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