PT-2025-8898 · Linux+8 · Linux Kernel+8

Cheung Wall

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Published

2025-01-13

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Updated

2026-04-20

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CVE-2025-21786

CVSS v3.1

7.8

High

VectorAV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)
Description A use-after-free bug was reported in the Linux kernel, specifically in the workqueue module. The issue arises from a commit that reaps normal workers but fails to handle the rescuer, leading to a situation where the pool's reference is not held until the detachment is complete. This results in a use-after-free bug. The bug was reported by Cheung Wall.
Recommendations To resolve the issue, the code that puts the pwq should be moved after detaching the rescuer from the pool, ensuring the pool's reference is held until the detachment is complete. At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Exploit

Use After Free

Weakness Enumeration

CWE-416

Related Identifiers

ALSA-2025:20095
ALSA-2025:20518
ALT-PU-2025-12647
AZL-58887
AZL-58922
BDU:2025-04525
CVE-2025-21786
INFSA-2025_20518
RHSA-2025:20095
RHSA-2025:20518
RHSA-2025_20518
RHSA-2026:2352
USN-7521-1
USN-7521-2
USN-7521-3
USN-7703-1
USN-7703-2
USN-7703-3
USN-7703-4
USN-7719-1
USN-7737-1

Affected Products

Alt Linux
Almalinux
Astra Linux
Debian
Linuxmint
Linux Kernel
Red Hat
Rocky Linux
Ubuntu