---
title: "CVE-2026-99231: Linux Kernel io_uring - Use After Free"
description: "Linux kernel io_uring contains a use-after-free vulnerability caused by improper ownership handling of requests before clearing ->head in io_waitid functions, letting attackers cause kernel memory corruption, exploit requires triggering specific io_uring operations."
url: https://panop.io/threat-heartbeat/CVE-2026-99231/
---

# CVE-2026-99231 Linux Kernel io\_uring - Use After Free

Linux kernel io\_uring contains a use-after-free vulnerability caused by improper ownership handling of requests before clearing ->head in io\_waitid functions, letting attackers cause kernel memory corruption, exploit requires triggering specific io\_uring operations.

CVSS base score 7.8 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Required

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-99231)

## Details

Type

Use After Free

Impact

Denial Of Service, Privilege Escalation

CVSS vector

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

Published

2 November 2026

Updated

3 November 2026

## Vendor fix

Update to the latest Linux kernel version containing the fix for io\_uring request ownership handling.

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-2026-99231](https://nvd.nist.gov/vuln/detail/CVE-2026-99231)
- [https://git.kernel.org/stable/c/bf01da1a9cca4a54e5c30b8344e52c26afb87be7](https://git.kernel.org/stable/c/bf01da1a9cca4a54e5c30b8344e52c26afb87be7)
- [https://git.kernel.org/stable/c/c10ad2813e15186fb51b37a4d17fafddc99e89a5](https://git.kernel.org/stable/c/c10ad2813e15186fb51b37a4d17fafddc99e89a5)
- [https://git.kernel.org/stable/c/8381a912c65b8de16e8a848225c7c5a56b6ea834](https://git.kernel.org/stable/c/8381a912c65b8de16e8a848225c7c5a56b6ea834)

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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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