---
title: "CVE-2026-99227: Linux Kernel - Race Condition"
description: "Linux kernel io_uring contains a reference wrap vulnerability caused by improper handling of cancellation state in io_waitid, letting attackers cause double completion of requests, exploit requires repeated cancellation attempts."
url: https://panop.io/threat-heartbeat/CVE-2026-99227/
---

# CVE-2026-99227 Linux Kernel - Race Condition

Linux kernel io\_uring contains a reference wrap vulnerability caused by improper handling of cancellation state in io\_waitid, letting attackers cause double completion of requests, exploit requires repeated cancellation attempts.

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-2026-99227)

## Details

Type

Race Condition

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

2 November 2026

Updated

3 November 2026

## Vendor fix

Update to the latest Linux kernel version containing the fix for io\_uring cancellation reference wrap.

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-2026-99227](https://nvd.nist.gov/vuln/detail/CVE-2026-99227)
- [https://git.kernel.org/stable/c/22fb4a4518e305164c7f203608287564de292f34](https://git.kernel.org/stable/c/22fb4a4518e305164c7f203608287564de292f34)
- [https://git.kernel.org/stable/c/5bfeee1774791602a0d53eb717f00f172127a017](https://git.kernel.org/stable/c/5bfeee1774791602a0d53eb717f00f172127a017)
- [https://git.kernel.org/stable/c/857aa2012b91cad6fdef54a4b6c632d9d0b6e64f](https://git.kernel.org/stable/c/857aa2012b91cad6fdef54a4b6c632d9d0b6e64f)
- [https://git.kernel.org/stable/c/20b67288574c7c3df6b8ea7ed3b7af90a868006f](https://git.kernel.org/stable/c/20b67288574c7c3df6b8ea7ed3b7af90a868006f)

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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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