Linux Kernel io_uring/poll Vulnerability Affecting Multiple Distributions

CVE-2026-99263

What is CVE-2026-99263?

A vulnerability in the Linux kernel's io_uring/poll implementation could lead to request processing delays. When a wakeup event triggers the IO_POLL_RETRY_FLAG, it may stall the current request processing until another unrelated wakeup occurs. This can adversely affect system performance and responsiveness. By implementing atomic_cmpxchg, the latest updates ensure that both the count and poll_refs are verified to be zero, preventing missed wake-ups and improving reliability.

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