CVE-2025-21786
Linux Kernel Workqueue Use-After-Free Vulnerability
Description
In the Linux kernel, the following vulnerability has been resolved: workqueue: Put the pwq after detaching the rescuer from the pool The commit 68f83057b913("workqueue: Reap workers via kthread_stop() and remove detach_completion") adds code to reap the normal workers but mistakenly does not handle the rescuer and also removes the code waiting for the rescuer in put_unbound_pool(), which caused a use-after-free bug reported by Cheung Wall. To avoid the use-after-free bug, the pool’s reference must be held until the detachment is complete. Therefore, move the code that puts the pwq after detaching the rescuer from the pool.
INFO
Published Date :
Feb. 27, 2025, 3:15 a.m.
Last Modified :
March 21, 2025, 3:43 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
Solution
- Update the Linux kernel to include the fix for the workqueue vulnerability.
- Ensure the rescuer is detached before the pool is freed.
- Verify that the pool's reference is held until detachment is complete.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2025-21786.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-21786 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2025-21786
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2025-21786 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2025-21786 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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Initial Analysis by [email protected]
Mar. 21, 2025
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.13 up to (excluding) 6.13.4 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions up to (excluding) 6.12.16 Added Reference Type kernel.org: https://git.kernel.org/stable/c/835b69c868f53f959d4986bbecd561ba6f38e492 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/e76946110137703c16423baf6ee177b751a34b7e Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/e7c16028a424dd35be1064a68fa318be4359310f Types: Patch -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Feb. 27, 2025
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Added CWE CWE-416 -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Feb. 27, 2025
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: workqueue: Put the pwq after detaching the rescuer from the pool The commit 68f83057b913("workqueue: Reap workers via kthread_stop() and remove detach_completion") adds code to reap the normal workers but mistakenly does not handle the rescuer and also removes the code waiting for the rescuer in put_unbound_pool(), which caused a use-after-free bug reported by Cheung Wall. To avoid the use-after-free bug, the pool’s reference must be held until the detachment is complete. Therefore, move the code that puts the pwq after detaching the rescuer from the pool. Added Reference https://git.kernel.org/stable/c/835b69c868f53f959d4986bbecd561ba6f38e492 Added Reference https://git.kernel.org/stable/c/e76946110137703c16423baf6ee177b751a34b7e Added Reference https://git.kernel.org/stable/c/e7c16028a424dd35be1064a68fa318be4359310f