Description
In the Linux kernel, the following vulnerability has been resolved:

io_uring/timeout: don't lose a cancel as io-wq arms a timeout

An IORING_OP_TIMEOUT run by io-wq, because of IOSQE_ASYNC, has the same
problem as poll, futex and waitid. io_wq_submit_work() looks at
IO_WQ_WORK_CANCEL once, before it issues the request. A cancel in between
flags the work, gets -EALREADY, and searches ->timeout_list in vain,
while the worker then adds the request and starts the timer:

io-wq worker io_try_cancel()
io_wq_submit_work()
IO_WQ_WORK_CANCEL isn't set
io_async_cancel_one()
sets IO_WQ_WORK_CANCEL
= -EALREADY
io_timeout_cancel() = -ENOENT
io_timeout()
adds the request to ->timeout_list
hrtimer_start()
= IOU_ISSUE_SKIP_COMPLETE

Nobody looks at the flag again, and the timeout runs its course. At ring
exit, io_uring_try_cancel_requests() cancels io-wq work and then kills
the timeouts the same way, so an exiting task can get stuck for the full
duration of such a timeout.

Look at the flag under ->timeout_lock, which the search takes as well,
and fail the request if it is set. If the search came first, the flag is
visible. If it comes later, it finds the request on the list.
Published: 2026-11-03
Score: n/a
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

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History

Tue, 03 Nov 2026 19:30:00 +0000


Tue, 03 Nov 2026 14:15:00 +0000

Type Values Removed Values Added
First Time appeared Linux linux
Weaknesses CWE-400
CWE-847
Vendors & Products Linux linux

Tue, 03 Nov 2026 12:00:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: io_uring/timeout: don't lose a cancel as io-wq arms a timeout An IORING_OP_TIMEOUT run by io-wq, because of IOSQE_ASYNC, has the same problem as poll, futex and waitid. io_wq_submit_work() looks at IO_WQ_WORK_CANCEL once, before it issues the request. A cancel in between flags the work, gets -EALREADY, and searches ->timeout_list in vain, while the worker then adds the request and starts the timer: io-wq worker io_try_cancel() io_wq_submit_work() IO_WQ_WORK_CANCEL isn't set io_async_cancel_one() sets IO_WQ_WORK_CANCEL = -EALREADY io_timeout_cancel() = -ENOENT io_timeout() adds the request to ->timeout_list hrtimer_start() = IOU_ISSUE_SKIP_COMPLETE Nobody looks at the flag again, and the timeout runs its course. At ring exit, io_uring_try_cancel_requests() cancels io-wq work and then kills the timeouts the same way, so an exiting task can get stuck for the full duration of such a timeout. Look at the flag under ->timeout_lock, which the search takes as well, and fail the request if it is set. If the search came first, the flag is visible. If it comes later, it finds the request on the list.
Title io_uring/timeout: don't lose a cancel as io-wq arms a timeout
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-11-03T19:13:16.211Z

Reserved: 2026-09-25T10:25:14.404Z

Link: CVE-2026-99262

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-11-03T12:17:33.210

Modified: 2026-11-03T20:18:31.763

Link: CVE-2026-99262

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-11-03T14:00:19Z

Weaknesses