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CVE-2026-99229

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

Not scored
Published
Updated
Reserved
Assigned by
Linux

Description

In 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.

Scores

No CVSS score yet: neither the CNA, CISA nor NVD has scored this CVE. NVD status: Received.

EPSS (exploitation in 30 days)
Not scored

The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.

Affected products

  • Linux · Linux

    • affected 3fcf19d592d5cb63eb209400b22055651e3c27d0 – < bf1d2ed84b3162e3b0e0bb7018ac59147da6e975
    • affected 3fcf19d592d5cb63eb209400b22055651e3c27d0 – < a6cfc85c6bf9498aaf1978b503f9663635a1aa22
    • affected 3fcf19d592d5cb63eb209400b22055651e3c27d0 – < 4a89352edd8b3e20d1e1fb33f0fc297dd137149f
    • affected 3fcf19d592d5cb63eb209400b22055651e3c27d0 – < c347691e5dc5481b2d6943c123619e04847fb0dc

  • Linux · Linux

    • affected 6.3
    • unaffected < 6.3
    • unaffected 6.6.161 – ≤ 6.6.*
    • unaffected 6.12.115 – ≤ 6.12.*
    • unaffected 6.18.60 – ≤ 6.18.*
    • unaffected 7.2.14 – ≤ 7.2.*

References (4)

Sources

The same CVE in the primary databases and aggregators, to check against.

Record last updated .