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High severity7.8NVD Advisory· Published Jan 20, 2025· Updated Jul 30, 2026

CVE-2025-21655

CVE-2025-21655

Description

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

io_uring/eventfd: ensure io_eventfd_signal() defers another RCU period

io_eventfd_do_signal() is invoked from an RCU callback, but when dropping the reference to the io_ev_fd, it calls io_eventfd_free() directly if the refcount drops to zero. This isn't correct, as any potential freeing of the io_ev_fd should be deferred another RCU grace period.

Just call io_eventfd_put() rather than open-code the dec-and-test and free, which will correctly defer it another RCU grace period.

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Affected products

148

Patches

Vulnerability mechanics

References

7

News mentions

1