CVE-2026-81010
Received Received - Intake

Linux Kernel Task Work Cancellation in io_uring

Vulnerability report for CVE-2026-81010, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-09-11

Last updated on: 2026-09-11

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: io_uring/waitid: honor task_work cancellation io_waitid_cb() may run through the fallback task_work path when task_work_add() can no longer queue work to the originating task. The fallback runs from a kworker and io_uring marks such task work as canceled through tw.cancel. io_waitid_cb() currently ignores tw.cancel and calls __do_wait(). waitid is task-context dependent: __do_wait() performs child lookup relative to current, and the retry path also uses current->signal->wait_chldexit. If the callback runs from the fallback kworker, current is therefore not the task that submitted the request. Honor tw.cancel before entering __do_wait(). Complete the request with -ECANCELED and skip the siginfo copy, since canceled task work may run without the submitting task's userspace execution context. Keep the existing siginfo handling for normal waitid completion and explicit cancellation.

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Meta Information

Published
2026-09-11
Last Modified
2026-09-11
Generated
2026-09-12
AI Q&A
2026-09-12
EPSS Evaluated
N/A
NVD
EUVD

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves io_uring's waitid operation not properly handling task_work cancellation. When task_work_add() fails to queue work to the original task, a fallback kworker executes the task. The io_waitid_cb() function ignores cancellation signals and proceeds with child process lookup using the wrong task context, leading to incorrect behavior.

Impact Analysis

This flaw could allow an attacker to manipulate waitid operations by exploiting improper task context handling. It may lead to incorrect process state tracking, potential privilege escalation, or denial of service if exploited in systems using io_uring with waitid.

Mitigation Strategies

Update the Linux kernel to a patched version that includes the fix for CVE-2026-81010. Monitor official Linux kernel security advisories for the specific kernel version addressing this issue.

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