CVE-2026-23473

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

io_uring/poll: fix multishot recv missing EOF on wakeup race

When a socket send and shutdown() happen back-to-back, both fire

wake-ups before the receiver's task_work has a chance to run. The first

wake gets poll ownership (poll_refs=1), and the second bumps it to 2.

When io_poll_check_events() runs, it calls io_poll_issue() which does a

recv that reads the data and returns IOU_RETRY. The loop then drains all

accumulated refs (atomic_sub_return(2) -> 0) and exits, even though only

the first event was consumed. Since the shutdown is a persistent state

change, no further wakeups will happen, and the multishot recv can hang

forever.

Check specifically for HUP in the poll loop, and ensure that another

loop is done to check for status if more than a single poll activation

is pending. This ensures we don't lose the shutdown event.