---
title: "CVE-2026-90243: Linux Kernel - Broken Authentication"
description: "Linux kernel contains a broken authentication caused by improper clearing of the Present bit before tearing down copied context entries in iommu/vt-d, letting hardware fetch torn entries causing unpredictable behavior or faults, exploit requires specific hardware conditions."
url: https://panop.io/threat-heartbeat/CVE-2026-90243/
---

# CVE-2026-90243 Linux Kernel - Broken Authentication

Linux kernel contains a broken authentication caused by improper clearing of the Present bit before tearing down copied context entries in iommu/vt-d, letting hardware fetch torn entries causing unpredictable behavior or faults, exploit requires specific hardware conditions.

CVSS base score 8.1 /10

High

CISA KEV

Not listed

Public exploit

None known

EPSS

0.16% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-90243)

## Details

Type

Broken Authentication

Impact

Denial Of Service

CVSS vector

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

Published

17 September 2026

Updated

15 October 2026

## Vendor fix

Update to the latest Linux kernel version containing the fix for iommu/vt-d context entry handling.

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-2026-90243](https://nvd.nist.gov/vuln/detail/CVE-2026-90243)
- [https://git.kernel.org/stable/c/3c88cfedc7768b1ae2dc7ddc71547ae9a1aaff7d](https://git.kernel.org/stable/c/3c88cfedc7768b1ae2dc7ddc71547ae9a1aaff7d)
- [https://git.kernel.org/stable/c/6b822d18c33af9d1e16a8e5e6aa6e656987b09de](https://git.kernel.org/stable/c/6b822d18c33af9d1e16a8e5e6aa6e656987b09de)
- [https://git.kernel.org/stable/c/97750a8dce79c1a9b2b2d2a020b61b800141996c](https://git.kernel.org/stable/c/97750a8dce79c1a9b2b2d2a020b61b800141996c)
- [https://git.kernel.org/stable/c/f532c57985b1a7d6b7e37e05506b46d413e5cca4](https://git.kernel.org/stable/c/f532c57985b1a7d6b7e37e05506b46d413e5cca4)

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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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