---
id: CVE-2026-89695
title: 'kernel: nfsd: cap decoded POSIX ACL count to bound sort cost (CVE-2026-89695)'
summary: >-
  A flaw was found in the Linux kernel's Network File System Daemon (nfsd). The
  `nfsd4_decode_posixacl()` function, responsible for decoding POSIX Access
  Control Lists (ACLs), does not properly cap the entry count received from a
  client. A r…
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-606
vendor: Red Hat
product: Red Hat OpenShift Container Platform 4
affected:
  - openshift_container_platform 4
published: '2026-09-11'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T12:25:18+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89695.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89695.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89695'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532373'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89695'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89695'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89695.mbox
  - url: 'https://git.kernel.org/stable/c/4bc1108e876153a2dd6d874052b99182c3603135'
  - url: 'https://git.kernel.org/stable/c/ea14d71d6ecb925673761bcf79f781f7dc9042cc'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
  - score-dispute
epss: 0.00488
epssPercentile: 0.41104
scores:
  vendor: 5.3
  cna: 7.5
ingestedAt: '2026-09-14T15:23:07.472Z'
---

## Overview

A flaw was found in the Linux kernel's Network File System Daemon (nfsd). The `nfsd4_decode_posixacl()` function, responsible for decoding POSIX Access Control Lists (ACLs), does not properly cap the entry count received from a client. A remote attacker can exploit this by sending a specially crafted ACL with an excessively large entry count, leading to unbounded CPU usage during an O(n^2) sorting operation. This can result in a Denial of Service (DoS) for the affected server.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat OpenShift Container Platform 4 · updated 2026-09-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89695.json)

**kernel: nfsd: cap decoded POSIX ACL count to bound sort cost** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-16.

Affected:

- Red Hat OpenShift Container Platform 4

No fix planned:

- Red Hat OpenShift Container Platform 4

## Remediation

Fix deferred