CVE Watch14 jul 2026

CVE-2025-21655

In the Linux kernel, the following vulnerability has been resolved: io_uring/eventfd: ensure io_eventfd_signal() defers another RCU period

CVSS

4.7

Medio

EPSS

0.2%

p12

KEV

—

Exploit Today

0-100

Publicado: 20 ene 2025 · Última mod.: 14 jul 2026 · CWE-416

EPSS · 30d

0.2%EPSS · 30 días0.2%

2026-06-302026-07-17

Descripción técnica

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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