---
title: "CVE-2026-89493: Linux Kernel ocfs2 - Out of Bounds Read & Write"
description: "Linux kernel ocfs2 contains an out-of-bounds read and write caused by missing validation of rl_used and rl_count fields in refcount block, letting local attackers with CAP_SYS_ADMIN mount crafted or corrupted images to cause memory corruption, exploit requires CAP_SYS_ADMIN privileges."
url: https://panop.io/threat-heartbeat/CVE-2026-89493/
---

# CVE-2026-89493 Linux Kernel ocfs2 - Out of Bounds Read & Write

Linux kernel ocfs2 contains an out-of-bounds read and write caused by missing validation of rl\_used and rl\_count fields in refcount block, letting local attackers with CAP\_SYS\_ADMIN mount crafted or corrupted images to cause memory corruption, exploit requires CAP\_SYS\_ADMIN privileges.

CVSS base score 8.8 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Required

EPSS

0.65% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-89493)

## Details

Type

Out of Bounds Read

Impact

Denial Of Service, Remote Code Execution

CVSS vector

CVSS:3.1/AV:N/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 containing the fix for ocfs2 refcount block 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-2026-89493](https://nvd.nist.gov/vuln/detail/CVE-2026-89493)
- [https://git.kernel.org/stable/c/c8b02f4ee91e757b3fff556c7168b24b7ae55132](https://git.kernel.org/stable/c/c8b02f4ee91e757b3fff556c7168b24b7ae55132)
- [https://git.kernel.org/stable/c/f882e9e32d017a6569b2996c63ba3864717788e6](https://git.kernel.org/stable/c/f882e9e32d017a6569b2996c63ba3864717788e6)
- [https://git.kernel.org/stable/c/04ead708e13ddcb9c39319cbe02a18cef99cb823](https://git.kernel.org/stable/c/04ead708e13ddcb9c39319cbe02a18cef99cb823)
- [https://git.kernel.org/stable/c/0761d2c9494424469a0d30a9da3496ca010b0b2d](https://git.kernel.org/stable/c/0761d2c9494424469a0d30a9da3496ca010b0b2d)
- [https://git.kernel.org/stable/c/4ca62df6bc0708947b48da3f6a712ecb8e73929c](https://git.kernel.org/stable/c/4ca62df6bc0708947b48da3f6a712ecb8e73929c)
- [https://git.kernel.org/stable/c/af56e90cb546cb0c47bef059335365283f61d6a4](https://git.kernel.org/stable/c/af56e90cb546cb0c47bef059335365283f61d6a4)
- [https://git.kernel.org/stable/c/5593b63028cb43a6cda75a65ce1db95f00ea6857](https://git.kernel.org/stable/c/5593b63028cb43a6cda75a65ce1db95f00ea6857)
- [https://git.kernel.org/stable/c/97584e93fc49a2d59252ac60467e9279f11b1b5b](https://git.kernel.org/stable/c/97584e93fc49a2d59252ac60467e9279f11b1b5b)

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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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