---
title: "CVE-2026-89442: Linux Kernel - Out of Bounds Read/Write"
description: "Linux kernel contains a buffer overflow caused by improper validation of socket_id in ISST clos_assoc ioctl, letting local attackers cause out-of-bounds access and NULL pointer dereference, exploit requires local access."
url: https://panop.io/threat-heartbeat/CVE-2026-89442/
---

# CVE-2026-89442 Linux Kernel - Out of Bounds Read/Write

Linux kernel contains a buffer overflow caused by improper validation of socket\_id in ISST clos\_assoc ioctl, letting local attackers cause out-of-bounds access and NULL pointer dereference, exploit requires local access.

CVSS base score 7.8 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Required

EPSS

0.17% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-89442)

## Details

Type

Out of Bounds Read/Write

Impact

Denial Of Service

CVSS vector

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

Published

11 September 2026

Updated

15 October 2026

## Vendor fix

Update to the latest Linux kernel version with the fix for ISST clos\_assoc 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-2026-89442](https://nvd.nist.gov/vuln/detail/CVE-2026-89442)
- [https://git.kernel.org/stable/c/82e707eff9e3b7ef6d96ecc23ea8876d20c7d6ca](https://git.kernel.org/stable/c/82e707eff9e3b7ef6d96ecc23ea8876d20c7d6ca)
- [https://git.kernel.org/stable/c/a89f07db0cb95c54dac4a8406c79a04e44a73c3c](https://git.kernel.org/stable/c/a89f07db0cb95c54dac4a8406c79a04e44a73c3c)
- [https://git.kernel.org/stable/c/c847ea4851ecfa3462cc711ded2c3c3dd8d08ab8](https://git.kernel.org/stable/c/c847ea4851ecfa3462cc711ded2c3c3dd8d08ab8)
- [https://git.kernel.org/stable/c/0d90ab5f80e19cddfeb0c9fab47a1f34aa932075](https://git.kernel.org/stable/c/0d90ab5f80e19cddfeb0c9fab47a1f34aa932075)
- [https://git.kernel.org/stable/c/207b4dc6eb100141b122b2602504a1429a4b6558](https://git.kernel.org/stable/c/207b4dc6eb100141b122b2602504a1429a4b6558)

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## 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

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