io_uring/wait: don't spin on a stuck overflow list

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-99229
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-11-02 16:17:47 UTC
Updated2026-11-06 18:18:32 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: io_uring/wait: don't spin on a stuck overflow list As long as IO_CHECK_CQ_OVERFLOW_BIT is set, io_cqring_wait_schedule() returns right away, before it gets to look at signals or arms the timeout, for io_cqring_wait() to flush the overflow list. If that doesn't empty the list, and the CQ ring doesn't hold the number of events the caller wants, the loop starts over, with the same result. The task spins in the kernel, and can't be killed. The assumption is that this can't happen: if CQEs can't be flushed, the ring is full, and min_events is capped to the size of the ring. But: - With IORING_SETUP_CQE_MIXED a 32b CQE needs two contiguous entries. It is stuck on the list if a single one is free, and then the ring holds less than cq_entries events. A single threaded application that asks for as many events as the ring has entries never gets out of io_uring_enter(). - Whether the ring is full is up to the CQ head, which the application can write to. While one thread waits for events on an empty ring, another one can move the head back so that the ring looks full and have a CQE overflow. The waiter can't be stopped any more, not even by SIGKILL. Only the application can make room in the CQ ring. Return to it if the list could not be flushed.

Risk And Classification

EPSS: 0.001570000 probability, percentile 0.048340000 (date 2026-11-03)

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 3fcf19d592d5cb63eb209400b22055651e3c27d0 bf1d2ed84b3162e3b0e0bb7018ac59147da6e975 git Not specified
CNA Linux Linux affected 3fcf19d592d5cb63eb209400b22055651e3c27d0 a6cfc85c6bf9498aaf1978b503f9663635a1aa22 git Not specified
CNA Linux Linux affected 3fcf19d592d5cb63eb209400b22055651e3c27d0 4a89352edd8b3e20d1e1fb33f0fc297dd137149f git Not specified
CNA Linux Linux affected 3fcf19d592d5cb63eb209400b22055651e3c27d0 c347691e5dc5481b2d6943c123619e04847fb0dc git Not specified
CNA Linux Linux affected 3fcf19d592d5cb63eb209400b22055651e3c27d0 340944e27b4bb218ed0ee66d0947ac70faefa05a git Not specified
CNA Linux Linux affected 3fcf19d592d5cb63eb209400b22055651e3c27d0 34f5a664c34d3cb62f6bec7f4156754594a7d25b git Not specified
CNA Linux Linux affected 6.3 Not specified
CNA Linux Linux unaffected 6.3 semver Not specified
CNA Linux Linux unaffected 6.6.161 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.115 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.60 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.14 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3.2 7.3.* semver Not specified
CNA Linux Linux unaffected 7.4-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/340944e27b4bb218ed0ee66d0947ac70faefa05a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/34f5a664c34d3cb62f6bec7f4156754594a7d25b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/a6cfc85c6bf9498aaf1978b503f9663635a1aa22 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/bf1d2ed84b3162e3b0e0bb7018ac59147da6e975 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/4a89352edd8b3e20d1e1fb33f0fc297dd137149f 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/c347691e5dc5481b2d6943c123619e04847fb0dc 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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