---
title: "CVE-2026-90231: Linux Kernel - Privilege Escalation"
description: "Linux kernel contains a privilege escalation caused by improper enforcement of unconfined user namespace restrictions in AppArmor stack transitions, letting unprivileged users escape confinement, exploit requires two transitions through an unconfined profile."
url: https://panop.io/threat-heartbeat/CVE-2026-90231/
---

# CVE-2026-90231 Linux Kernel - Privilege Escalation

Linux kernel contains a privilege escalation caused by improper enforcement of unconfined user namespace restrictions in AppArmor stack transitions, letting unprivileged users escape confinement, exploit requires two transitions through an unconfined profile.

CVSS base score 8.4 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Required

EPSS

0.17% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-90231)

## Details

Type

Privilege Escalation

Impact

Privilege Escalation

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N

Published

17 September 2026

Updated

15 October 2026

## Vendor fix

Update to the latest Linux kernel version with the AppArmor fix applied.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-90231](https://nvd.nist.gov/vuln/detail/CVE-2026-90231)
- [https://git.kernel.org/stable/c/08c2f7c8d4b1434cfae006f3daf4d1bce330b57b](https://git.kernel.org/stable/c/08c2f7c8d4b1434cfae006f3daf4d1bce330b57b)
- [https://git.kernel.org/stable/c/7d1099b86356df81c379159bfb8a598aaf83ce81](https://git.kernel.org/stable/c/7d1099b86356df81c379159bfb8a598aaf83ce81)
- [https://git.kernel.org/stable/c/7da0bdf0610f6d35bbb061536a47fc41646306f0](https://git.kernel.org/stable/c/7da0bdf0610f6d35bbb061536a47fc41646306f0)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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