---
title: "CVE-2026-89488: Linux Kernel openvswitch - Use After Free"
description: "Linux kernel openvswitch contains a use-after-free vulnerability caused by improper handling of CT limit state under RCU and ovs_mutex during netns teardown, letting unprivileged users trigger slab-use-after-free in ovs_ct_execute(), exploit requires user and network namespace access."
url: https://panop.io/threat-heartbeat/CVE-2026-89488/
---

# CVE-2026-89488 Linux Kernel openvswitch - Use After Free

Linux kernel openvswitch contains a use-after-free vulnerability caused by improper handling of CT limit state under RCU and ovs\_mutex during netns teardown, letting unprivileged users trigger slab-use-after-free in ovs\_ct\_execute(), exploit requires user and network namespace access.

CVSS base score 7.8 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Required

EPSS

0.13% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-89488)

## Details

Type

Use After Free

Impact

Denial Of Service, Remote Code Execution

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 containing the fix for CT limit teardown use-after-free.

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-2026-89488](https://nvd.nist.gov/vuln/detail/CVE-2026-89488)
- [https://git.kernel.org/stable/c/6a6d36fadb8537d9b79e72c9fa51885ec0c33e10](https://git.kernel.org/stable/c/6a6d36fadb8537d9b79e72c9fa51885ec0c33e10)
- [https://git.kernel.org/stable/c/e15407c3a8a005324f633cd46cd8fb58042c1157](https://git.kernel.org/stable/c/e15407c3a8a005324f633cd46cd8fb58042c1157)
- [https://git.kernel.org/stable/c/239f26589a6926db28c436e14f28517581ef1385](https://git.kernel.org/stable/c/239f26589a6926db28c436e14f28517581ef1385)
- [https://git.kernel.org/stable/c/3b41d907400cc1dd1da9555b81dca422b1f44433](https://git.kernel.org/stable/c/3b41d907400cc1dd1da9555b81dca422b1f44433)
- [https://git.kernel.org/stable/c/3b9369881b403f4cdbb11fa998554382bdcc3d8c](https://git.kernel.org/stable/c/3b9369881b403f4cdbb11fa998554382bdcc3d8c)
- [https://git.kernel.org/stable/c/680f20d5937fa4d1367c59fe83091b78041015f5](https://git.kernel.org/stable/c/680f20d5937fa4d1367c59fe83091b78041015f5)
- [https://git.kernel.org/stable/c/bf4aaa7ea2579e24ed7de2e20578a875bebca011](https://git.kernel.org/stable/c/bf4aaa7ea2579e24ed7de2e20578a875bebca011)
- [https://git.kernel.org/stable/c/403f96c32c9e24600093d7d0c61c17daeedca957](https://git.kernel.org/stable/c/403f96c32c9e24600093d7d0c61c17daeedca957)

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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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