---
id: CVE-2026-89689
title: 'kernel: nfsd: don''t free session slots that are still in use (CVE-2026-89689)'
summary: >-
  A flaw was found in the Linux kernel's Network File System (NFS) daemon,
  `nfsd`. A remote attacker could exploit a use-after-free vulnerability in the
  `nfsd4_sequence()` function. This occurs when the system attempts to reduce
  the number o…
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-825
vendor: Red Hat
product: Red Hat Enterprise Linux 10
affected:
  - enterprise_linux 10
  - enterprise_linux 6
published: '2026-09-11'
updated: '2026-09-15'
sourceUpdated: '2026-09-15T11:30:21+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89689.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89689.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89689'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532497'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89689'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89689'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89689.mbox
  - url: 'https://git.kernel.org/stable/c/72d40b103bb03f0124d3a3c8f71a30cbafaf6afa'
  - url: 'https://git.kernel.org/stable/c/b449b134e7762ddf98653a4b1d3e76d2d212ea64'
  - url: 'https://git.kernel.org/stable/c/f5d22e372f4ac3eb287037a488c29691d52a6330'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
  - score-dispute
epss: 0.00605
epssPercentile: 0.47679
scores:
  vendor: 7.4
  cna: 9.8
ingestedAt: '2026-09-14T15:23:07.473Z'
---

## Overview

A flaw was found in the Linux kernel's Network File System (NFS) daemon, `nfsd`. A remote attacker could exploit a use-after-free vulnerability in the `nfsd4_sequence()` function. This occurs when the system attempts to reduce the number of active session slots while a client is still using one of the slots being freed. Successful exploitation leads to memory corruption, which can result in a denial of service or other system instability.

## Vendor advisories

- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6 · no fix planned: Red Hat Enterprise Linux 10 · updated 2026-09-15 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89689.json)

**kernel: nfsd: don't free session slots that are still in use** — rated Important by Red Hat. Released 2026-09-11, updated 2026-09-15.

Affected:

- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6

No fix planned:

- Red Hat Enterprise Linux 10

Not affected:

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

## Remediation

Affected