---
title: "CVE-2026-89775: Linux Kernel KVM arm64 - Denial of Service"
description: "Linux kernel KVM arm64 contains a logic error caused by improper handling of negative S1 walk levels in VNCR TLB size evaluation, letting attackers potentially cause incorrect TLB invalidation size calculation, exploit requires kernel-level access."
url: https://panop.io/threat-heartbeat/CVE-2026-89775/
---

# CVE-2026-89775 Linux Kernel KVM arm64 - Denial of Service

Linux kernel KVM arm64 contains a logic error caused by improper handling of negative S1 walk levels in VNCR TLB size evaluation, letting attackers potentially cause incorrect TLB invalidation size calculation, exploit requires kernel-level access.

CVSS base score 9.3 /10

Critical

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.23% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-89775)

## Details

Type

Denial of Service

Impact

Denial Of Service

CVSS vector

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

Published

16 September 2026

Updated

15 October 2026

## Vendor fix

Update to the latest Linux kernel version containing the fix for negative S1 walk levels in VNCR TLB size evaluation.

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-2026-89775](https://nvd.nist.gov/vuln/detail/CVE-2026-89775)
- [https://git.kernel.org/stable/c/1c9fca34b9625a67a7f1a03c8604f3df760c6c49](https://git.kernel.org/stable/c/1c9fca34b9625a67a7f1a03c8604f3df760c6c49)
- [https://git.kernel.org/stable/c/8053393680d4fa3eb962667d2be95dd39f0940e5](https://git.kernel.org/stable/c/8053393680d4fa3eb962667d2be95dd39f0940e5)
- [https://git.kernel.org/stable/c/be54a70067c7dbe1381157e8a238fa4b16ea9c05](https://git.kernel.org/stable/c/be54a70067c7dbe1381157e8a238fa4b16ea9c05)
- [http://www.openwall.com/lists/oss-security/2026/09/16/14](http://www.openwall.com/lists/oss-security/2026/09/16/14)

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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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