---
id: CVE-2026-89691
title: >-
  kernel: nfsd: clear opcnt on compound arg release to prevent OOB read
  (CVE-2026-89691)
summary: >-
  A flaw was found in the Linux kernel's Network File System Daemon (nfsd)
  component. The nfsd4_release_compoundargs() function does not properly clear
  an internal counter (opcnt) when releasing a buffer. This oversight can lead
  to an out-of…
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-125
vendor: Red Hat
product: Red Hat Enterprise Linux 9
affected:
  - enterprise_linux 10
  - enterprise_linux 6
  - enterprise_linux 9
  - openshift_container_platform 4
published: '2026-09-11'
updated: '2026-09-21'
sourceUpdated: '2026-09-21T11:44:27+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89691.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89691.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89691'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532399'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89691'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89691'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89691.mbox
  - url: 'https://git.kernel.org/stable/c/58bcdfb2b2e412088839ae740b1a95154dc0b8d0'
  - url: 'https://git.kernel.org/stable/c/ae4c38555e81563b8dc5eae55ffd70f0ea97aa5a'
  - url: 'https://git.kernel.org/stable/c/c1a4f7b1848f95302df598217e1c7a1410c2d0c5'
  - url: 'https://git.kernel.org/stable/c/e879148867bd4c4cac42e063ffaffa187dddc6fe'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
epss: 0.00125
epssPercentile: 0.0254
scores:
  vendor: 7.4
  cna: 7.1
ingestedAt: '2026-09-14T15:23:07.473Z'
---

## Overview

A flaw was found in the Linux kernel's Network File System Daemon (nfsd) component. The nfsd4_release_compoundargs() function does not properly clear an internal counter (opcnt) when releasing a buffer. This oversight can lead to an out-of-bounds read, allowing an attacker to access adjacent memory and potentially leak sensitive information to userspace through netlink.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89691.json)

**kernel: nfsd: clear opcnt on compound arg release to prevent OOB read** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-21.

Affected:

- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4

No fix planned:

- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4

Not affected:

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

## Remediation

Out of support scope