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Use After Free The advisory has been revoked - it doesn't affect any version of package kernel-devel-matched  (opens in a new tab)

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EPSS
0.02% (5th percentile)

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  • Snyk IDSNYK-ALMALINUX10-KERNELDEVELMATCHED-14118294
  • published26 Nov 2025
  • disclosed11 Nov 2025
Report a new vulnerability Found a mistake?

Introduced: 11 Nov 2025

CVE-2025-21655  (opens in a new tab)
CWE-416  (opens in a new tab)

Amendment

The AlmaLinux security team deemed this advisory irrelevant for AlmaLinux:10.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-devel-matched package and not the kernel-devel-matched package as distributed by AlmaLinux.

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.