---
id: CVE-2026-89667
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  nfsd: close shrinker/GC/fsnotify vs per-net shutdown race in filecache

  The shrinker, GC worker, and fsnotify/lease callbacks can unhash an
  nfsd_file from the rhashtabl…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  nfsd: close shrinker/GC/fsnotify vs per-net shutdown race in filecache

  The shrinker, GC worker, and fsnotify/lease callbacks can unhash an
  nfsd_file from the rhashtabl…
severity: high
cvss: 8.1
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-772
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= ffb402596147ac583f3464ff5c48feb9423e3838 <
    b15997b53b61c74fb4d083f7261d19f389ff854f
  - >-
    Linux >= ffb402596147ac583f3464ff5c48feb9423e3838 <
    6d6b9f6a75c3767250e9c23ace4e384ab8f7843e
  - >-
    Linux >= ffb402596147ac583f3464ff5c48feb9423e3838 <
    08af9593e2b472fd98c00faf1bf03bdbb7203477
  - >-
    Linux >= ffb402596147ac583f3464ff5c48feb9423e3838 <
    40162cfea79b9510380decfdd1795b754dc9f972
  - Linux 6.9
published: '2026-09-11'
updated: '2026-09-21'
sourceUpdated: '2026-09-21T14:17:24.830'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89667'
references:
  - url: 'https://git.kernel.org/stable/c/08af9593e2b472fd98c00faf1bf03bdbb7203477'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/40162cfea79b9510380decfdd1795b754dc9f972'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/6d6b9f6a75c3767250e9c23ace4e384ab8f7843e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/b15997b53b61c74fb4d083f7261d19f389ff854f'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89667.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89667'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532484'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89667'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89667'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89667.mbox
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
  - score-dispute
epss: 0.0053
epssPercentile: 0.43755
scores:
  nvd: 8.1
  cna: 8.1
  vendor: 5.5
ingestedAt: '2026-09-14T15:23:07.473Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

nfsd: close shrinker/GC/fsnotify vs per-net shutdown race in filecache

The shrinker, GC worker, and fsnotify/lease callbacks can unhash an
nfsd_file from the rhashtable and then call
nfsd_file_dispose_list_delayed() to move it to the per-net dispose list.
If nfsd_file_cache_shutdown_net() runs concurrently, its rhashtable walk
misses the already-unhashed file, and its drain of the per-net dispose
list can run before the file has been queued.  The file then sits on
the per-net list with no thread to drain it, leaking both the file and
its associated state.

The GC worker and shrinker already hold nfsd_gc_lock while walking the
LRU, but in the original code they release it before calling
nfsd_file_dispose_list_delayed().  The fsnotify/lease path
(nfsd_file_close_inode) has no synchronization at all.

Fix this by:

  1. Widening nfsd_gc_lock in both nfsd_file_gc() and nfsd_file_lru_scan()
     to cover the nfsd_file_dispose_list_delayed() call.

  2. Wrapping nfsd_file_close_inode() in nfsd_gc_lock so that all three
     callers of nfsd_file_dispose_list_delayed() hold the lock.

  3. Adding a spin_lock/unlock(nfsd_gc_lock) barrier in
     nfsd_file_cache_shutdown_net() after the purge, so that any
     in-progress disposal has fully completed before the per-net list
     is drained.

All operations inside the lock are non-sleeping (rhashtable lookups,
atomic bit/refcount ops, list moves, svc_wake_up), so the spinlock is
appropriate.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-09-15 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89667.json)