Live › vulnerability › CVE-2026-99262
In the Linux kernel's io_uring, a cancel request that arrives while an io-wq worker is starting a timeout can be dropped, so the timeout keeps running. An exiting task can then stay stuck for the full timeout duration.
Summary written from the sources below. Check the originals before acting.
First seen by InfraStack 2026-11-03 12:20 UTC. All times on this page are UTC.
Systems running a Linux kernel with io_uring, where applications submit IORING_OP_TIMEOUT requests with IOSQE_ASYNC. The sources do not give affected kernel version ranges or a fix commit. Systems without io_uring, or without this request pattern, are unlikely to be affected.
No product ranges from the sources yet.
Unknown from the sources.
Unknown from the sources.
Each row is the first time that source carried this signal. The analyst’s rows are its own findings.
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.
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