CVE-2026-80920 - io_uring: defer eventfd signaling when queued from a wakeup handler

CVE-2026-80920 - io_uring: defer eventfd signaling when queued from a wakeup handler

https://cvefeed.io/rssfeed/latest.atom / Wed, 09/09/2026 - 22:31
CVE ID :CVE-2026-80920
Published : Sept. 9, 2026, 5:17 p.m. | 1 hour, 48 minutes ago
Description :In the Linux kernel, the following vulnerability has been resolved: io_uring: defer eventfd signaling when queued from a wakeup handler io_req_local_work_add() signals the CQ ring eventfd inline when it is the one to push the first entry onto ->work_list. For DEFER_TASKRUN rings that add is frequently done from a waitqueue wakeup handler, where an arbitrary waitqueue lock is held. eventfd_signal_mask() only refuses to recurse when current->in_eventfd is set, but that bit is set by eventfd_signal_mask() itself. If the wake chain starts somewhere else, signal goes out inline and can feed back into epoll. Add IOU_F_TWQ_IN_WAKE, set it on the task_work add done from the three waitqueue callbacks, and use it to force io_eventfd_signal() down the existing call_rcu_hurry() deferral instead of signaling inline.
Severity: 0.0 | NA
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