---
id: CVE-2026-89439
title: 'kernel: platform/x86: ISST: Add a NULL check for sst_inst[] (CVE-2026-89439)'
summary: >-
  A flaw was found in the Linux kernel's Intel Speed Select Technology (ISST)
  driver. A missing NULL check for `isst_common.sst_inst[]` during failed socket
  loading could allow a local attacker to trigger a NULL pointer dereference.
  This vul…
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-476
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: '2026-09-14T21:37:38+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89439.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89439.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89439'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532216'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89439'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89439'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89439.mbox
  - url: 'https://git.kernel.org/stable/c/49a95fe1f64f41c2e8959e525aefdb10f23b293e'
  - url: 'https://git.kernel.org/stable/c/c280fcd53b938b70c7dee9ce1a66b32bd6e5ebaa'
  - url: 'https://git.kernel.org/stable/c/ef7975af15126dd70ace519da7bb33f2848b9064'
  - url: 'https://git.kernel.org/stable/c/3de2776e9d7073765c10c2326c2bda5926811ea6'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
epss: 0.002
epssPercentile: 0.10135
ingestedAt: '2026-09-14T00:35:28.531Z'
---

## Overview

A flaw was found in the Linux kernel's Intel Speed Select Technology (ISST) driver. A missing NULL check for `isst_common.sst_inst[]` during failed socket loading could allow a local attacker to trigger a NULL pointer dereference. This vulnerability could lead to a system crash, resulting in a Denial of Service (DoS).

## Vendor advisories

- **Red Hat VEX** · Low · 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-2026-89439.json)

**kernel: platform/x86: ISST: Add a NULL check for sst_inst[]** — rated Low 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