---
id: CVE-2026-89686
title: >-
  kernel: nfsd: fix BUG_ON in nfsd4_alloc_layout_stateid on racing delegation
  revoke (CVE-2026-89686)
summary: >-
  A flaw was found in the Linux kernel's Network File System Daemon (nfsd) for
  NFSv4 layouts. A race condition allows a remote attacker to trigger a kernel
  panic, leading to a Denial of Service (DoS). This occurs when the
  `nfsd4_alloc_layout…
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 7
  - enterprise_linux 8
  - enterprise_linux 9
  - openshift_container_platform 4
published: '2026-09-11'
updated: '2026-09-21'
sourceUpdated: '2026-09-21T11:41:19+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89686.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89686.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89686'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532098'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89686'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89686'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89686.mbox
  - url: 'https://git.kernel.org/stable/c/607a56fea772c1f4f4989d8e255dd4f7192d9604'
  - url: 'https://git.kernel.org/stable/c/97bda8b4284d90897a1f1922e5082ff9e35d7c7e'
  - url: 'https://git.kernel.org/stable/c/c517f27498757e616d2a8fe6d16caad1fee422e6'
  - url: 'https://git.kernel.org/stable/c/ca94ba36172046be6a694a7986f6931e47ed4d51'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
  - score-dispute
epss: 0.00671
epssPercentile: 0.50595
scores:
  vendor: 5.3
  cna: 9.8
ingestedAt: '2026-09-14T15:23:07.473Z'
---

## Overview

A flaw was found in the Linux kernel's Network File System Daemon (nfsd) for NFSv4 layouts. A race condition allows a remote attacker to trigger a kernel panic, leading to a Denial of Service (DoS). This occurs when the `nfsd4_alloc_layout_stateid` function accesses a file pointer without proper locking during a concurrent delegation revoke, which can be orchestrated by two NFS clients interacting with the same file.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: 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 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, … · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89686.json)

**kernel: nfsd: fix BUG_ON in nfsd4_alloc_layout_stateid on racing delegation revoke** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-21.

Affected:

- 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

No fix planned:

- 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

Not affected:

- Red Hat Enterprise Linux 6

## Remediation

Affected