---
id: CVE-2026-89670
title: 'kernel: nfsd: hold rcu across localio cmpxchg retry (CVE-2026-89670)'
summary: >-
  A flaw was found in the Linux kernel's Network File System Daemon (nfsd)
  component. A race condition exists in the `nfsd_open_local_fh()` function
  where an `nfsd_file` object can be freed and its memory recycled while another
  process attem…
severity: medium
cvss: 4.7
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H'
cvssSource: vendor
cwe:
  - CWE-416
  - CWE-825
vendor: Red Hat
product: Red Hat Enterprise Linux 10
affected:
  - enterprise_linux 10
published: '2026-09-11'
updated: '2026-10-21'
sourceUpdated: '2026-10-21T09:59:24+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89670.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89670.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89670'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532286'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89670'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89670'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89670.mbox
  - url: 'https://kernelcve.org/list/?q=CVE-2026-89670'
  - url: 'https://git.kernel.org/stable/c/763c0bad872368304db718f79af7e93048885c67'
  - url: 'https://git.kernel.org/stable/c/559570f91a7d4d199a72105e4980bef791f4cbf1'
  - url: 'https://git.kernel.org/stable/c/58884694978a3d7d111edb433d7fd6a6c5af2f34'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
epss: 0.00173
epssPercentile: 0.06733
scores:
  vendor: 7
  cna: 7.8
ingestedAt: '2026-09-14T15:23:07.473Z'
---

## Overview

A flaw was found in the Linux kernel's Network File System Daemon (nfsd) component. A race condition exists in the `nfsd_open_local_fh()` function where an `nfsd_file` object can be freed and its memory recycled while another process attempts to access it. This can lead to a use-after-free vulnerability, allowing an attacker to potentially cause memory corruption, disclose sensitive information, or execute arbitrary code.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10 · no fix planned: Red Hat Enterprise Linux 10 · updated 2026-10-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89670.json)

**kernel: nfsd: hold rcu across localio cmpxchg retry** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-10-21.

Affected:

- Red Hat Enterprise Linux 10

No fix planned:

- Red Hat Enterprise Linux 10

Not affected:

- 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

## Remediation

Fix deferred

Workarounds / mitigations:

- Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.