---
title: "CVE-2026-89674: Linux Kernel - Buffer Overflow & Information Disclosure"
description: "Linux kernel contains a buffer overflow and information disclosure vulnerability caused by incorrect XDR length calculation in nfsd4_ff_encode_layoutget, letting remote attackers cause out-of-bounds write or leak uninitialized kernel memory, exploit requires crafted NFSv4 requests."
url: https://panop.io/threat-heartbeat/CVE-2026-89674/
---

# CVE-2026-89674 Linux Kernel - Buffer Overflow & Information Disclosure

Linux kernel contains a buffer overflow and information disclosure vulnerability caused by incorrect XDR length calculation in nfsd4\_ff\_encode\_layoutget, letting remote attackers cause out-of-bounds write or leak uninitialized kernel memory, exploit requires crafted NFSv4 requests.

CVSS base score 9.8 /10

Critical

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.51% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-89674)

## Details

Type

Buffer Overflow

Impact

Denial Of Service, Information Disclosure

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 nfsd4\_ff\_encode\_layoutget XDR length calculation.

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-2026-89674](https://nvd.nist.gov/vuln/detail/CVE-2026-89674)
- [https://git.kernel.org/stable/c/29e4478e2ed5a227e8f0c33cacb91bf227cedd47](https://git.kernel.org/stable/c/29e4478e2ed5a227e8f0c33cacb91bf227cedd47)
- [https://git.kernel.org/stable/c/3a7fd224df0fbb42167eb1b77be45d72fe0b1098](https://git.kernel.org/stable/c/3a7fd224df0fbb42167eb1b77be45d72fe0b1098)
- [https://git.kernel.org/stable/c/65a72b721943618eeb3a41c8b36e915591f3f83f](https://git.kernel.org/stable/c/65a72b721943618eeb3a41c8b36e915591f3f83f)
- [https://git.kernel.org/stable/c/bee826c00ac900473f91306f1f3e5a5a81fd4a74](https://git.kernel.org/stable/c/bee826c00ac900473f91306f1f3e5a5a81fd4a74)
- [https://git.kernel.org/stable/c/0380129b1373c437eb35401a174671c8888f4b80](https://git.kernel.org/stable/c/0380129b1373c437eb35401a174671c8888f4b80)
- [https://git.kernel.org/stable/c/c81cef6a805dec266c10fc4f83c93d6fcf1a2b43](https://git.kernel.org/stable/c/c81cef6a805dec266c10fc4f83c93d6fcf1a2b43)
- [https://git.kernel.org/stable/c/e7d9d23ecd9172f05b09bb678ff22db8e361c428](https://git.kernel.org/stable/c/e7d9d23ecd9172f05b09bb678ff22db8e361c428)
- [https://git.kernel.org/stable/c/f9868174af49d207fbaf0c5e055d088a983684af](https://git.kernel.org/stable/c/f9868174af49d207fbaf0c5e055d088a983684af)

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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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