---
id: CVE-2026-89571
title: >-
  kernel: cxl/features: bound fwctl command payload to the input buffer
  (CVE-2026-89571)
summary: >-
  A flaw was found in the Linux kernel's CXL (Compute Express Link) features. A
  local attacker could exploit an out-of-bounds read vulnerability in the
  `fwctl_cmd_rpc()` and `cxlctl_set_feature()` functions. This occurs when the
  system attem…
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cvssSource: vendor
cwe: CWE-125
vendor: Red Hat
product: Red Hat OpenShift Container Platform 4
affected:
  - openshift_container_platform 4
published: '2026-09-11'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T22:07:25+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89571.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89571.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89571'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532280'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89571'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89571'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89571.mbox
  - url: 'https://git.kernel.org/stable/c/14d52c15d5d99477b20a2d61fe36f347080da6cd'
  - url: 'https://git.kernel.org/stable/c/d8957545fe96f7905791c937758ebfc1ae1e5b17'
  - url: 'https://git.kernel.org/stable/c/f687394af983df5660b6afae7e0d06969f3af206'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
  - score-dispute
epss: 0.00124
epssPercentile: 0.02437
scores:
  vendor: 4.4
  cna: 7.1
ingestedAt: '2026-09-14T15:23:07.474Z'
---

## Overview

A flaw was found in the Linux kernel's CXL (Compute Express Link) features. A local attacker could exploit an out-of-bounds read vulnerability in the `fwctl_cmd_rpc()` and `cxlctl_set_feature()` functions. This occurs when the system attempts to copy data with a small input buffer length but processes a larger, user-controlled operation size without proper validation. This can lead to reading beyond the allocated memory, causing a kernel crash and resulting in a denial of service.

## Vendor advisories

- **Red Hat VEX** · Moderate · updated 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89571.json)

**kernel: cxl/features: bound fwctl command payload to the input buffer** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-18.

Not affected:

- Red Hat Enterprise Linux 10
- 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

Refer to the advisory for fix availability.