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CVE-2026-90231

8.4 · HIGH

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 tran…

Published Sep 17, 2026EPSS 0.17%

Overview

CVE-2026-90231 is a high-severity vulnerability. It was published on September 17, 2026 and has a CVSS 3.1 base score of 8.4 (HIGH).

This vulnerability has a CVSS 3.1 base score of 8.4, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

Technical 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.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refgit.kernel.org/stable/c/08c2f7c8d4b1434cfae006f3daf4d1bce330b57bRefgit.kernel.org/stable/c/7d1099b86356df81c379159bfb8a598aaf83ce81Refgit.kernel.org/stable/c/7da0bdf0610f6d35bbb061536a47fc41646306f0Refgit.kernel.org/stable/c/fdd341654471cae4fbd9635d32b848cd0c8bc437

How CyberStrike helps

Frequently asked questions

What is CVE-2026-90231?

CVE-2026-90231 is a high-severity vulnerability. It was published on September 17, 2026 and has a CVSS 3.1 base score of 8.4 (HIGH).

How severe is CVE-2026-90231?

This vulnerability has a CVSS 3.1 base score of 8.4, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2026-90231?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-90231?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-90231 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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