---
title: "CVE-2026-80921: Linux Kernel KVM s390 - Broken Access Control"
description: "Linux kernel KVM s390 contains a broken access control vulnerability caused by stale crypto bits in vsie page allowing nested guests potential unauthorized device access, exploit requires nested guest environment."
url: https://panop.io/threat-heartbeat/CVE-2026-80921/
---

# CVE-2026-80921 Linux Kernel KVM s390 - Broken Access Control

Linux kernel KVM s390 contains a broken access control vulnerability caused by stale crypto bits in vsie page allowing nested guests potential unauthorized device access, exploit requires nested guest environment.

CVSS base score 8.8 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Required

EPSS

0.13% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-80921)

## Details

Type

Broken Access Control

Impact

Broken Access Control

CVSS vector

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

Published

9 September 2026

Updated

15 October 2026

## Vendor fix

Update to the latest Linux kernel version with the 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-2026-80921](https://nvd.nist.gov/vuln/detail/CVE-2026-80921)
- [https://git.kernel.org/stable/c/087c19cc60a8caa1a08e1e434c8be2caf6c27733](https://git.kernel.org/stable/c/087c19cc60a8caa1a08e1e434c8be2caf6c27733)
- [https://git.kernel.org/stable/c/29b4f7bc2991313bd3e6f6fb8fdf1b173f086dd6](https://git.kernel.org/stable/c/29b4f7bc2991313bd3e6f6fb8fdf1b173f086dd6)
- [https://git.kernel.org/stable/c/34d5b5b646c91cfb9338d7a12c955a70ffb8c66b](https://git.kernel.org/stable/c/34d5b5b646c91cfb9338d7a12c955a70ffb8c66b)
- [https://git.kernel.org/stable/c/59d51550b5cb916bda037673a721a404b3b47a0d](https://git.kernel.org/stable/c/59d51550b5cb916bda037673a721a404b3b47a0d)
- [https://git.kernel.org/stable/c/7d23489f51109e3ebba5b5db8c5f0185af7b7fdf](https://git.kernel.org/stable/c/7d23489f51109e3ebba5b5db8c5f0185af7b7fdf)
- [https://git.kernel.org/stable/c/935eeba276012916c76243e5cbb843efd8fdb75d](https://git.kernel.org/stable/c/935eeba276012916c76243e5cbb843efd8fdb75d)
- [https://git.kernel.org/stable/c/d110b3297f11ef227098b8a82ade2d5f123b7d2f](https://git.kernel.org/stable/c/d110b3297f11ef227098b8a82ade2d5f123b7d2f)
- [https://git.kernel.org/stable/c/d4bcd2df6d0d2af916b4fe1a533958778ea7c45b](https://git.kernel.org/stable/c/d4bcd2df6d0d2af916b4fe1a533958778ea7c45b)
- [https://git.kernel.org/stable/c/f6079dca67eccb5eabef9f72437948c66dc5131f](https://git.kernel.org/stable/c/f6079dca67eccb5eabef9f72437948c66dc5131f)

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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

Panop answers these inside your environment, for this CVE and every other finding.

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