---
id: CVE-2026-89662
title: >-
  kernel: NFSD: Prevent lock owner use-after-free during client teardown
  (CVE-2026-89662)
summary: >-
  A flaw was found in the Linux kernel's Network File System Daemon (NFSD).
  During client teardown, a race condition can occur where a lock owner is freed
  while still being referenced, leading to a use-after-free vulnerability. This
  can resu…
severity: high
cvss: 7
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: vendor
cwe: CWE-476
vendor: Red Hat
product: Red Hat Enterprise Linux 9
affected:
  - enterprise_linux 10
  - enterprise_linux 6
  - enterprise_linux 7
  - enterprise_linux 8
  - enterprise_linux 9
  - openshift_container_platform 4
published: '2026-09-11'
updated: '2026-09-15'
sourceUpdated: '2026-09-15T13:23:52+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89662.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89662.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89662'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532486'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89662'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89662'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89662.mbox
  - url: 'https://git.kernel.org/stable/c/42d7954b0a1907d4ef122aef94561952a033cdc3'
  - url: 'https://git.kernel.org/stable/c/bb38ff8b4dafbbd1781ad37cd96722fdf2cd972a'
  - url: 'https://git.kernel.org/stable/c/b8bad5a11416b26cc7fd4b18fba46d75ff636558'
  - url: 'https://git.kernel.org/stable/c/1ce74d1b7770e69735e8f8e509807af4ff9c8ee7'
  - url: 'https://git.kernel.org/stable/c/a6ead6fff3a7d03e49845f048f7000a2e0d34431'
  - url: 'https://git.kernel.org/stable/c/4804c58f73a80d12df1de323bf97a164f6ee8743'
  - url: 'https://git.kernel.org/stable/c/8cf4ff0a7c083dd5e0067f517d63979b74b66649'
  - url: 'https://git.kernel.org/stable/c/5e2fa29d223a9a1e6a948e40b109d09081d1decd'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
  - score-dispute
epss: 0.00734
epssPercentile: 0.52364
scores:
  vendor: 7
  cna: 9.8
ingestedAt: '2026-09-14T15:23:07.450Z'
---

## Overview

A flaw was found in the Linux kernel's Network File System Daemon (NFSD). During client teardown, a race condition can occur where a lock owner is freed while still being referenced, leading to a use-after-free vulnerability. This can result in a NULL dereference, potentially causing a system crash and a denial of service.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · updated 2026-09-15 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89662.json)

**kernel: NFSD: Prevent lock owner use-after-free during client teardown** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-15.

Affected:

- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4

No fix planned:

- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4

## Remediation

Out of support scope