---
title: "CVE-2026-89443: Linux Kernel - Out-of-Bounds Read"
description: "Linux kernel contains an out-of-bounds read vulnerability caused by lack of validation of user-provided level in perf mask ioctls in platform/x86 ISST component, letting attackers cause memory disclosure, exploit requires crafted ioctl input."
url: https://panop.io/threat-heartbeat/CVE-2026-89443/
---

# CVE-2026-89443 Linux Kernel - Out-of-Bounds Read

Linux kernel contains an out-of-bounds read vulnerability caused by lack of validation of user-provided level in perf mask ioctls in platform/x86 ISST component, letting attackers cause memory disclosure, exploit requires crafted ioctl input.

CVSS base score 7.1 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Required

EPSS

0.16% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-89443)

## Details

Type

Out-of-Bounds Read

Impact

Information Disclosure

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Published

11 September 2026

Updated

15 October 2026

## Vendor fix

Update to the latest Linux kernel version with the fix for ISST perf mask ioctl validation.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-89443](https://nvd.nist.gov/vuln/detail/CVE-2026-89443)
- [https://git.kernel.org/stable/c/1889a9156553f0692acd57caf15e877baace1a01](https://git.kernel.org/stable/c/1889a9156553f0692acd57caf15e877baace1a01)
- [https://git.kernel.org/stable/c/1a8bab5ceee1a42a78de12d3d69f67516a20588e](https://git.kernel.org/stable/c/1a8bab5ceee1a42a78de12d3d69f67516a20588e)
- [https://git.kernel.org/stable/c/80e0d353c86a9a168ad6d213f494796294381538](https://git.kernel.org/stable/c/80e0d353c86a9a168ad6d213f494796294381538)
- [https://git.kernel.org/stable/c/d19385624bdfb577db9c94bb8879992fd5e17bcd](https://git.kernel.org/stable/c/d19385624bdfb577db9c94bb8879992fd5e17bcd)
- [https://git.kernel.org/stable/c/beb22ebf76c0415f22d2d0c3f1ff0627e7ae4a68](https://git.kernel.org/stable/c/beb22ebf76c0415f22d2d0c3f1ff0627e7ae4a68)

[← All CVEs](https://panop.io/threat-heartbeat/)

## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

Panop answers these inside your environment, for this CVE and every other finding.

[Book a demo](https://panop.io/demo)