PT-2025-9007 · Linux+6 · Linux Kernel+6

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CVE-2025-21816

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Published

2025-01-18

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Updated

2026-05-26

CVSS v3.1

5.5

Medium

VectorAV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)
Description A vulnerability in the Linux kernel's hrtimers infrastructure allows wakeups to be performed by an outgoing CPU after the CPUHP AP HRTIMERS DYING stage, potentially resulting in bandwidth timers being armed on an offline CPU. This issue affects not only RCU but also other components, such as the stop machine kthread, which can report its completion and perform a wake up that arms the deadline server timer. The problem is resolved by migrating away timers to an online target whenever they are enqueued from an offline CPU.
Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Exploit

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Weakness Enumeration

Related Identifiers

AZL-68823
BDU:2025-15112
CVE-2025-21816
DLA-4328-1
DSA-5973-1
ECHO-E970-49FC-8B64
OESA-2025-1371
OESA-2025-1372
OESA-2025-1409
OESA-2025-1410
OPENSUSE-SU-2025:20091-1
SUSE-SU-2025:21080-1
SUSE-SU-2025:21147-1
SUSE-SU-2025:21180-1
SUSE-SU-2025_21147-1
SUSE-SU-2026:20561-1
USN-7521-1
USN-7521-2
USN-7521-3
USN-7651-1
USN-7651-2
USN-7651-3
USN-7651-4
USN-7651-5
USN-7651-6
USN-7652-1
USN-7653-1
USN-7737-1

Affected Products

Astra Linux
Debian
Linuxmint
Linux Kernel
Red Os
Suse
Ubuntu