CVE-2025-21661: linux kernel — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: gpio: virtuser: fix missing lookup table cleanups When a virtuser device is created via configfs and the probe fails due to an incorrect lookup table, the table is not removed. This prevents subsequent probe attempts from succeeding, even if the issue is corrected, unless the device is released. Additionally, cleanup is also needed in the less likely case of platform_device_register_full() failure. Besides, a consistent memory leak in lookup_table->dev_id was spotted using kmemleak by toggling the live state between 0 and 1 with a correct lookup table. Introduce gpio_virtuser_remove_lookup_table() as the counterpart to the existing gpio_virtuser_make_lookup_table() and call it from all necessary points to ensure proper cleanup.

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CVSS v3.1 Score

5.5

MEDIUM

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

Weakness Type (CWE)

CWE-401 CWE-401

Affected Products

Vendor	Product	Versions
linux	linux_kernel	6.11 — 6.12.10
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All

References

Advisories & Patches

https://git.kernel.org/stable/c/a619cba8c69c434258ff4101d463322cd63e1bdc https://git.kernel.org/stable/c/d72d0126b1f6981f6ce8b4247305f359958c11b5

Frequently Asked Questions

What is CVE-2025-21661? +

In the Linux kernel, the following vulnerability has been resolved: gpio: virtuser: fix missing lookup table cleanups When a virtuser device is created via configfs and the probe fails due to an incorrect lookup table, the table is not removed. This prevents subsequent probe attempts from succeeding, even if the issue is corrected, unless the device is released. Additionally, cleanup is also needed in the less likely case of platform_device_register_full() failure. Besides, a consistent memory leak in lookup_table->dev_id was spotted using kmemleak by toggling the live state between 0 and 1 with a correct lookup table. Introduce gpio_virtuser_remove_lookup_table() as the counterpart to the existing gpio_virtuser_make_lookup_table() and call it from all necessary points to ensure proper cleanup. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2025-21661? +

CVE-2025-21661 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-21661? +

CVE-2025-21661 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-2025-21661? +

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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