---
id: CVE-2026-89713
title: 'kernel: NFSD: check truncate permission under inode lock (CVE-2026-89713)'
summary: >-
  A flaw was found in the Linux kernel's Network File System Daemon (NFSD). A
  remote attacker, by sending a crafted file attribute modification request
  (SETATTR) while a file is being concurrently appended, could exploit a
  time-of-check to t…
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-367
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
  - enterprise_linux 6
published: '2026-09-11'
updated: '2026-09-21'
sourceUpdated: '2026-09-21T16:29:47+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89713.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89713.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89713'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532459'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89713'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89713'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89713.mbox
  - url: 'https://git.kernel.org/stable/c/3afa17d93ba8c925f49370c816c6dae5112d8c24'
  - url: 'https://git.kernel.org/stable/c/44086254479035de42ca3d286ecf25521d4e6325'
  - url: 'https://git.kernel.org/stable/c/b778e0e0a16759f22a70579c3cf8d254a40d4a7f'
  - url: 'https://git.kernel.org/stable/c/d8352da196349182e1afd5a93308256cddc0a97d'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
  - score-dispute
epss: 0.00647
epssPercentile: 0.48919
scores:
  vendor: 6.8
  cna: 9.1
ingestedAt: '2026-09-14T15:23:07.472Z'
---

## Overview

A flaw was found in the Linux kernel's Network File System Daemon (NFSD). A remote attacker, by sending a crafted file attribute modification request (SETATTR) while a file is being concurrently appended, could exploit a time-of-check to time-of-use (TOCTOU) vulnerability. This could lead to the unauthorized truncation of append-only files, potentially resulting in data loss.

## Vendor advisories

- **Red Hat VEX** · Important · 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, Red Hat Enterprise Linux 6 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4, Red Hat Enterprise Linux 7, … · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89713.json)

**kernel: NFSD: check truncate permission under inode lock** — rated Important 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
- Red Hat Enterprise Linux 6

No fix planned:

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

## Remediation

Fix deferred