CVE-2026-89741

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

Revert "media: v4l2-dev: fix error handling in __video_register_device()"

This reverts commit 2a934fdb01db6458288fc9386d3d8ceba6dd551a.

The intentions of that patch were good, but it doesn't work.

The idea is that if device_register fails, you have to do a put_device

to let the ref counter release resources.

However, the V4L2 API says that if video_register_device() fails, then

you have to call video_device_release(), which kfree()s the video_device

struct.

But the put_device() will already have freed the struct, so you end

up in a double-free scenario.

There is not really a good way of fixing this without breaking

video_register_device() into two parts, one that initializes everything,

and one that does the actual device_register, and then converting all

V4L2 drivers to this new model.

That is a massive job, and it is very unlikely that device_register

will fail.

So rather than ending up in a double-free scen

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References