CVE-2026-89741: Revert "media: v4l2-dev: fix error handling in __video_register_device()"

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-11 · updated 2026-10-19

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 scenario, just revert this patch, and in that case we'll have a small memory leak. Which is a lot more robust.

Affected products

Linux kernel: from 5.10.239 before 5.10.270; from 5.15.186 before 5.15.221; from 6.1.142 before 6.1.188; from 6.6.95 before 6.6.157; from 6.12.35 before 6.12.109; from 5.4.295 before 5.5 — fixed in 5.10.270, 5.15.221, 5.5, 6.1.188, 6.12.109, 6.16

How to fix

Upgrade to a fixed version: Linux kernel 5.10.270, 5.15.221, 5.5, 6.1.188. Check the vendor advisory for mitigations.

References

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