---
id: CVE-2026-89587
title: >-
  kernel: ACPI: pfr_update: fix stack buffer overflow in query_capability()
  (CVE-2026-89587)
summary: >-
  A flaw was found in the Linux kernel's ACPI Platform Firmware Runtime Update
  (pfr_update) component. The `query_capability()` function, responsible for
  handling ACPI buffer objects from firmware, performs an unchecked memory copy
  operation…
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-120
vendor: Red Hat
product: Red Hat Enterprise Linux 9
affected:
  - enterprise_linux 10
  - enterprise_linux 9
  - openshift_container_platform 4
published: '2026-09-11'
updated: '2026-09-21'
sourceUpdated: '2026-09-21T16:49:16+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89587.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89587.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89587'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532213'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89587'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89587'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89587.mbox
  - url: 'https://git.kernel.org/stable/c/d3af83e327565a9444cebc0db714cb837e493046'
  - url: 'https://git.kernel.org/stable/c/c5a31b4e7e37c92550be9a2edf51ca853a4d251a'
  - url: 'https://git.kernel.org/stable/c/a2151624b55029dad0ca7efd17fb83a0461c8843'
  - url: 'https://git.kernel.org/stable/c/6d4ed2fd022bc862b156e53aae163b61259e1caa'
  - url: 'https://git.kernel.org/stable/c/15d2b7f38f95d28652170344f39ee492c55e567c'
  - url: 'https://git.kernel.org/stable/c/ced45be0073a8a31b30b4a7f68cd3a15734515de'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
epss: 0.00142
epssPercentile: 0.03928
scores:
  vendor: 7
  cna: 7.8
ingestedAt: '2026-09-14T15:23:07.451Z'
---

## Overview

A flaw was found in the Linux kernel's ACPI Platform Firmware Runtime Update (pfr_update) component. The `query_capability()` function, responsible for handling ACPI buffer objects from firmware, performs an unchecked memory copy operation. If the firmware provides an oversized buffer, a stack buffer overflow occurs, leading to memory corruption. This could allow a local attacker to cause a denial of service or potentially execute arbitrary code.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: 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-2026-89587.json)

**kernel: ACPI: pfr_update: fix stack buffer overflow in query_capability()** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-21.

Affected:

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

No fix planned:

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

Not affected:

- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat OpenShift Container Platform 4

## Remediation

Affected