CVE-2025-21655

CVE Details

Release Date:	2025-01-20
Impact:	Moderate	What is this?

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.

See more information about CVE-2025-21655 from MITRE CVE dictionary and NIST NVD

NOTE: The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 metrics

Base Score:	0.0
Vector String:	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:N
Version:	3.1
Attack Vector:	Local
Attack Complexity:	Low
Privileges Required:	Low
User Interaction:	None
Scope:	Unchanged
Confidentiality Impact:	None
Integrity Impact:	None
Availability Impact:	None

Errata information

Platform	Errata	Release Date
Oracle Linux version 10 (kernel)	ELSA-2025-20095-0	2025-11-25
Oracle Linux version 10 (kernel-uek)	ELSA-2025-20480	2025-07-17
Oracle Linux version 10 (kernel-uek)	ELSA-2025-20530	2025-08-18
Oracle Linux version 9 (kernel-uek)	ELSA-2025-20480	2025-07-17
Oracle Linux version 9 (kernel-uek)	ELSA-2025-20530	2025-08-18