---
title: "CVE-2026-89550: Linux Kernel - Denial of Service"
description: "Linux kernel contains a buffer length validation vulnerability in SUNRPC svcauth_gss component, caused by missing minimum length check on krb5 tokens, letting remote attackers cause a denial of service via crafted tokens, exploit requires network access."
url: https://panop.io/threat-heartbeat/CVE-2026-89550/
---

# CVE-2026-89550 Linux Kernel - Denial of Service

Linux kernel contains a buffer length validation vulnerability in SUNRPC svcauth\_gss component, caused by missing minimum length check on krb5 tokens, letting remote attackers cause a denial of service via crafted tokens, exploit requires network access.

CVSS base score 9.8 /10

Critical

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.46% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-89550)

## Details

Type

Denial of Service

Impact

Denial Of Service

CVSS vector

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

Published

11 September 2026

Updated

15 October 2026

## Vendor fix

Update to the latest Linux kernel version containing the fix for minimum length check in svcauth\_gss.

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-2026-89550](https://nvd.nist.gov/vuln/detail/CVE-2026-89550)
- [https://git.kernel.org/stable/c/de942dd8c2c8358bcad04ce44271954c48924423](https://git.kernel.org/stable/c/de942dd8c2c8358bcad04ce44271954c48924423)
- [https://git.kernel.org/stable/c/0ea5b0c7f212c2772d32c2b88287b89a9cdf6edd](https://git.kernel.org/stable/c/0ea5b0c7f212c2772d32c2b88287b89a9cdf6edd)
- [https://git.kernel.org/stable/c/2eed1e6a976a44015c3ee78841fe336796e2b21c](https://git.kernel.org/stable/c/2eed1e6a976a44015c3ee78841fe336796e2b21c)
- [https://git.kernel.org/stable/c/a919c5c88769cf8fb3ec071e6078d830bf512489](https://git.kernel.org/stable/c/a919c5c88769cf8fb3ec071e6078d830bf512489)
- [https://git.kernel.org/stable/c/dd6afc6cab8c5d387d1ed2f069562ef7bdadd651](https://git.kernel.org/stable/c/dd6afc6cab8c5d387d1ed2f069562ef7bdadd651)

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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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