---
id: CVE-2026-89443
title: 'platform/x86: ISST: Validate level in perf mask ioctls'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  platform/x86: ISST: Validate level in perf mask ioctls

  isst_if_get_perf_level_mask() and isst_if_get_base_freq_mask() use the
  user-provided level as an index into perf…
severity: high
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H'
cvssSource: cna
cwe:
  - CWE-125
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= ea009e4769fa3bd05d4c111c3b6865eb3a9be829 <
    beb22ebf76c0415f22d2d0c3f1ff0627e7ae4a68
  - >-
    Linux >= ea009e4769fa3bd05d4c111c3b6865eb3a9be829 <
    1a8bab5ceee1a42a78de12d3d69f67516a20588e
  - >-
    Linux >= ea009e4769fa3bd05d4c111c3b6865eb3a9be829 <
    1889a9156553f0692acd57caf15e877baace1a01
  - >-
    Linux >= ea009e4769fa3bd05d4c111c3b6865eb3a9be829 <
    d19385624bdfb577db9c94bb8879992fd5e17bcd
  - >-
    Linux >= ea009e4769fa3bd05d4c111c3b6865eb3a9be829 <
    80e0d353c86a9a168ad6d213f494796294381538
  - Linux 6.4
published: '2026-09-11'
updated: '2026-10-19'
sourceUpdated: '2026-10-19T08:46:52.766Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-89443'
references:
  - 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'
  - 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
tags:
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00163
epssPercentile: 0.05487
scores:
  cna: 7.1
  vendor: 5.5
ingestedAt: '2026-09-14T15:23:07.453Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

platform/x86: ISST: Validate level in perf mask ioctls

isst_if_get_perf_level_mask() and isst_if_get_base_freq_mask() use the
user-provided level as an index into perf_levels[] via
_read_pp_level_info() and _read_bf_level_info(), but neither helper
validates it first.

The adjacent level-info helpers reject levels above max_level before
reading the same per-level register block. Add the same bounds checks to
the mask helpers, and reject disabled SST-PP levels in
isst_if_get_perf_level_mask() to match isst_if_get_perf_level_info().

This prevents out-of-bounds reads from the per-level offset table on
invalid ioctl input.

## Affected

- `Linux >= ea009e4769fa3bd05d4c111c3b6865eb3a9be829 < beb22ebf76c0415f22d2d0c3f1ff0627e7ae4a68`
- `Linux >= ea009e4769fa3bd05d4c111c3b6865eb3a9be829 < 1a8bab5ceee1a42a78de12d3d69f67516a20588e`
- `Linux >= ea009e4769fa3bd05d4c111c3b6865eb3a9be829 < 1889a9156553f0692acd57caf15e877baace1a01`
- `Linux >= ea009e4769fa3bd05d4c111c3b6865eb3a9be829 < d19385624bdfb577db9c94bb8879992fd5e17bcd`
- `Linux >= ea009e4769fa3bd05d4c111c3b6865eb3a9be829 < 80e0d353c86a9a168ad6d213f494796294381538`
- `Linux 6.4`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## 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 2026-10-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89443.json)