CVE-2025-38584: linux kernel Use-After-Free — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: padata: Fix pd UAF once and for all There is a race condition/UAF in padata_reorder that goes back to the initial commit. A reference count is taken at the start of the process in padata_do_parallel, and released at the end in padata_serial_worker. This reference count is (and only is) required for padata_replace to function correctly. If padata_replace is never called then there is no issue. In the function padata_reorder which serves as the core of padata, as soon as padata is added to queue->serial.list, and the associated spin lock released, that padata may be processed and the reference count on pd would go away. Fix this by getting the next padata before the squeue->serial lock is released. In order to make this possible, simplify padata_reorder by only calling it once the next padata arrives.

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CVSS v3.1 Score

7.8

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Weakness Type (CWE)

CWE-416 Use After Free

Affected Products

Vendor	Product	Versions
linux	linux_kernel	2.6.34 — 6.15.10
linux	linux_kernel	6.16 — 6.16.1

References

Advisories & Patches

https://git.kernel.org/stable/c/71203f68c7749609d7fc8ae6ad054bdedeb24f91 https://git.kernel.org/stable/c/cdf79bd2e1ecb3cc75631c73d8f4149be6019a52 https://git.kernel.org/stable/c/dbe3e911a59bda6de96e7cae387ff882c2c177fa

Other References

https://git.kernel.org/stable/c/f231d5d001ec75f5886c02d496a4c79edc383d45

Frequently Asked Questions

What is CVE-2025-38584? +

In the Linux kernel, the following vulnerability has been resolved: padata: Fix pd UAF once and for all There is a race condition/UAF in padata_reorder that goes back to the initial commit. A reference count is taken at the start of the process in padata_do_parallel, and released at the end in padata_serial_worker. This reference count is (and only is) required for padata_replace to function correctly. If padata_replace is never called then there is no issue. In the function padata_reorder which serves as the core of padata, as soon as padata is added to queue->serial.list, and the associated spin lock released, that padata may be processed and the reference count on pd would go away. Fix this by getting the next padata before the squeue->serial lock is released. In order to make this possible, simplify padata_reorder by only calling it once the next padata arrives. It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2025-38584? +

CVE-2025-38584 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2025-38584? +

CVE-2025-38584 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-38584? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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