---
id: CVE-2026-89722
title: >-
  kernel: PCI/sysfs: Fix out-of-bounds read in pci_write_legacy_io()
  (CVE-2026-89722)
summary: >-
  A flaw was found in the Linux kernel's PCI/sysfs component. A local user with
  root privileges could trigger an out-of-bounds read in the
  `pci_write_legacy_io()` function by writing to the `legacy_io` sysfs file with
  a size less than four b…
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 Enterprise Linux 9
affected:
  - enterprise_linux 10
  - enterprise_linux 6
  - enterprise_linux 7
  - enterprise_linux 8
  - enterprise_linux 9
  - openshift_container_platform 4
published: '2026-09-11'
updated: '2026-09-15'
sourceUpdated: '2026-09-15T19:43:55+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89722.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89722.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89722'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532142'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89722'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89722'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89722.mbox
  - url: 'https://git.kernel.org/stable/c/7a99e9c7011905734cc2739038f2a224b6be0d1f'
  - url: 'https://git.kernel.org/stable/c/dc76258d0132df1d831a5a29758bd448ca9c566e'
  - url: 'https://git.kernel.org/stable/c/e892f05f1f790d5721cd8e3c561ed76da7e08bae'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
epss: 0.00198
epssPercentile: 0.0983
ingestedAt: '2026-09-14T15:23:07.476Z'
---

## Overview

A flaw was found in the Linux kernel's PCI/sysfs component. A local user with root privileges could trigger an out-of-bounds read in the `pci_write_legacy_io()` function by writing to the `legacy_io` sysfs file with a size less than four bytes. This improper handling of the write buffer can lead to memory corruption, potentially allowing for information disclosure or other system instability. On little-endian PowerPC systems, this could also result in an out-of-bounds write.

## Vendor advisories

- **Red Hat VEX** · Moderate · 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 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · updated 2026-09-15 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89722.json)

**kernel: PCI/sysfs: Fix out-of-bounds read in pci_write_legacy_io()** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-15.

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

No fix planned:

- Red Hat Enterprise Linux 6
- 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

## Remediation

Out of support scope