CVE-2026-80920
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.
Affected versions
Linux kernel versions
6.1
and later are affected. Fixed in
6.18.49,
7.1.11,
7.2.1,
7.3-rc1
and their respective stable series.
References
4 totalFrequently asked questions
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What is CVE-2026-80920?
CVE-2026-80920 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 6.1 onward and has been patched in 6.18.49, 7.1.11, 7.2.1 and others. CVE-2026-80920 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-80920?
Yes. CVE-2026-80920 has been patched. Fixed versions include 6.18.49, 7.1.11, 7.2.1 and others. If you are running Linux kernel 6.1 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-80920 actively exploited?
No. CVE-2026-80920 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.