---
id: CVE-2026-89443
title: >-
  kernel: platform/x86: ISST: Validate level in perf mask ioctls
  (CVE-2026-89443)
summary: >-
  A flaw was found in the Linux kernel's platform/x86 ISST module. The
  `isst_if_get_perf_level_mask()` and `isst_if_get_base_freq_mask()` functions
  fail to validate a user-provided 'level' parameter. A local attacker could
  exploit this by pr…
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 9
  - openshift_container_platform 4
published: '2026-09-11'
updated: '2026-09-14'
sourceUpdated: '2026-09-14T21:49:29+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89443.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89443.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89443'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532417'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89443'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89443'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89443.mbox
  - url: 'https://git.kernel.org/stable/c/beb22ebf76c0415f22d2d0c3f1ff0627e7ae4a68'
  - url: 'https://git.kernel.org/stable/c/1a8bab5ceee1a42a78de12d3d69f67516a20588e'
  - url: 'https://git.kernel.org/stable/c/1889a9156553f0692acd57caf15e877baace1a01'
  - url: 'https://git.kernel.org/stable/c/d19385624bdfb577db9c94bb8879992fd5e17bcd'
  - url: 'https://git.kernel.org/stable/c/80e0d353c86a9a168ad6d213f494796294381538'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
epss: 0.00166
epssPercentile: 0.05163
scores:
  vendor: 5.5
  cna: 7.1
ingestedAt: '2026-09-14T15:23:07.453Z'
---

## Overview

A flaw was found in the Linux kernel's platform/x86 ISST module. The `isst_if_get_perf_level_mask()` and `isst_if_get_base_freq_mask()` functions fail to validate a user-provided 'level' parameter. A local attacker could exploit this by providing an invalid 'level' value, leading to an out-of-bounds read from the per-level offset table. This could result in information disclosure or a denial of service (DoS).

## 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 2026-09-14 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89443.json)

**kernel: platform/x86: ISST: Validate level in perf mask ioctls** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-14.

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

Fix deferred