---
title: "CVE-2026-89540: Linux Kernel - Race Condition"
description: "Linux kernel contains a race condition in sunrpc where /proc/net/rpc/use-gss-proxy is published before initializing gssp_lock mutex, letting local userspace attackers cause mutex misuse and client leaks, exploit requires concurrent access during module load."
url: https://panop.io/threat-heartbeat/CVE-2026-89540/
---

# CVE-2026-89540 Linux Kernel - Race Condition

Linux kernel contains a race condition in sunrpc where /proc/net/rpc/use-gss-proxy is published before initializing gssp\_lock mutex, letting local userspace attackers cause mutex misuse and client leaks, exploit requires concurrent access during module load.

CVSS base score 7.8 /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-2026-89540)

## Details

Type

Race Condition

Impact

Denial Of Service

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/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 that initializes gssp\_lock in sunrpc\_init\_net.

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-2026-89540](https://nvd.nist.gov/vuln/detail/CVE-2026-89540)
- [https://git.kernel.org/stable/c/edeefb111d6181a4aa278f415b005efe284b9489](https://git.kernel.org/stable/c/edeefb111d6181a4aa278f415b005efe284b9489)
- [https://git.kernel.org/stable/c/f15b87521168c2a92cb1931f532cba422f856f01](https://git.kernel.org/stable/c/f15b87521168c2a92cb1931f532cba422f856f01)
- [https://git.kernel.org/stable/c/159a4fab7170badd6c4a553aef81cac079d6f4ee](https://git.kernel.org/stable/c/159a4fab7170badd6c4a553aef81cac079d6f4ee)
- [https://git.kernel.org/stable/c/7f5bcdc8da15077ebe846c2756a5a17741021410](https://git.kernel.org/stable/c/7f5bcdc8da15077ebe846c2756a5a17741021410)
- [https://git.kernel.org/stable/c/89c8e0733e8c46b7973503f15b1b31a8587d8030](https://git.kernel.org/stable/c/89c8e0733e8c46b7973503f15b1b31a8587d8030)
- [https://git.kernel.org/stable/c/b3526ae3351968f6726bcbe25d8d09973ad79109](https://git.kernel.org/stable/c/b3526ae3351968f6726bcbe25d8d09973ad79109)
- [https://git.kernel.org/stable/c/3f019571928b269feebcff59926ec13294215e0e](https://git.kernel.org/stable/c/3f019571928b269feebcff59926ec13294215e0e)
- [https://git.kernel.org/stable/c/5ce1ed6159731a41fdd0b03eedbed4e147036a5a](https://git.kernel.org/stable/c/5ce1ed6159731a41fdd0b03eedbed4e147036a5a)

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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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