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

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Summary

CVECVE-2026-23473
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-04-03 16:16:35 UTC
Updated2026-04-07 13:20:55 UTC
DescriptionIn 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.

Risk And Classification

EPSS: 0.000170000 probability, percentile 0.039750000 (date 2026-04-07)

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected dbc2564cfe0faff439dc46adb8c009589054ea46 0f4ce79b8db7b040373fc664c8bc6c5fd74bd196 git Not specified
CNA Linux Linux affected dbc2564cfe0faff439dc46adb8c009589054ea46 bf33554b6abf7e7faeadd8af1b82037ea755a6bb git Not specified
CNA Linux Linux affected dbc2564cfe0faff439dc46adb8c009589054ea46 a68ed2df72131447d131531a08fe4dfcf4fa4653 git Not specified
CNA Linux Linux affected 5.19 Not specified
CNA Linux Linux unaffected 5.19 semver Not specified
CNA Linux Linux unaffected 6.18.20 6.18.* semver Not specified
CNA Linux Linux unaffected 6.19.10 6.19.* semver Not specified
CNA Linux Linux unaffected 7.0-rc5 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/0f4ce79b8db7b040373fc664c8bc6c5fd74bd196 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/a68ed2df72131447d131531a08fe4dfcf4fa4653 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/bf33554b6abf7e7faeadd8af1b82037ea755a6bb 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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