Debian: CVE-2025-21655: linux -- security update

Debian: CVE-2025-21655: linux -- security update

Severity

4

CVSS

(AV:L/AC:M/Au:N/C:P/I:P/A:P)

Published

01/20/2025

Created

02/11/2025

Added

02/10/2025

Modified

02/10/2025

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.

Solution(s)

• debian-upgrade-linux

References

• https://attackerkb.com/topics/cve-2025-21655
• CVE - 2025-21655
• DSA-5860-1