---
title: "CVE-2026-89697: Linux Kernel - Broken Access Control"
description: "Linux kernel contains a broken access control vulnerability caused by missing fh_want_write() call in nfsd_proc_setattr() during early-verified SETATTR, letting attackers cause improper mount write reference handling, exploit requires network access to NFS service."
url: https://panop.io/threat-heartbeat/CVE-2026-89697/
---

# CVE-2026-89697 Linux Kernel - Broken Access Control

Linux kernel contains a broken access control vulnerability caused by missing fh\_want\_write() call in nfsd\_proc\_setattr() during early-verified SETATTR, letting attackers cause improper mount write reference handling, exploit requires network access to NFS service.

CVSS base score 9.1 /10

Critical

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.70% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-89697)

## Details

Type

Broken Access Control

Impact

Broken Access Control, Denial Of Service

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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 fh\_want\_write() in nfsd\_proc\_setattr().

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-2026-89697](https://nvd.nist.gov/vuln/detail/CVE-2026-89697)
- [https://git.kernel.org/stable/c/4e475be769aa9f7a2c1ce55a2b8592cfccacddcc](https://git.kernel.org/stable/c/4e475be769aa9f7a2c1ce55a2b8592cfccacddcc)
- [https://git.kernel.org/stable/c/533964d420d385e11b08dd4c56c66ef5dcccaf08](https://git.kernel.org/stable/c/533964d420d385e11b08dd4c56c66ef5dcccaf08)
- [https://git.kernel.org/stable/c/c4a409b86a92815181a8e9395c6bf1696ad19175](https://git.kernel.org/stable/c/c4a409b86a92815181a8e9395c6bf1696ad19175)
- [https://git.kernel.org/stable/c/2150305134889fb2fc25228d35353bd2f6f29500](https://git.kernel.org/stable/c/2150305134889fb2fc25228d35353bd2f6f29500)
- [https://git.kernel.org/stable/c/3eec9d791968c177a4a8cda9af5c04f79dae09cb](https://git.kernel.org/stable/c/3eec9d791968c177a4a8cda9af5c04f79dae09cb)
- [https://git.kernel.org/stable/c/9229d824b938f4fb0ea7a5dddade51735e6fe6f9](https://git.kernel.org/stable/c/9229d824b938f4fb0ea7a5dddade51735e6fe6f9)
- [https://git.kernel.org/stable/c/d823bf9285cdf4514873b85ab5a888878dd4e8f4](https://git.kernel.org/stable/c/d823bf9285cdf4514873b85ab5a888878dd4e8f4)
- [https://git.kernel.org/stable/c/15ca3b64a69caa6194bed8f98a20ed90a11c11dd](https://git.kernel.org/stable/c/15ca3b64a69caa6194bed8f98a20ed90a11c11dd)

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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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