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CVE-2026-89741
Revert "media: v4l2-dev: fix error handling in __video_register_device()"
Published 2026-09-11 (37 days ago) by the Linux kernel CNA. Subsystem drivers/media. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-89741 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | fixedDLA-4841-1 · 2026-10-17 · text | 6.1.190-1 | Update the kernel and reboot. DLA-4841-1 shipped the fix on 2026-10-17, in 6.1.190-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixedDSA-6528-1 · 2026-09-29 · text | 6.12.111-1 | Update the kernel and reboot. DSA-6528-1 shipped the fix on 2026-09-29, in 6.12.111-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.2.6-1 | Update the kernel and reboot. Fixed in 7.2.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.2.6-1 | Update the kernel and reboot. Fixed in 7.2.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4817-1 · 2026-10-04 · text | 6.12.111-1~deb12u1 | Update the kernel and reboot. DLA-4817-1 shipped the fix on 2026-10-04, in 6.12.111-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
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.
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
drivers/media/v4l2-core/v4l2-dev.c
- What this is
- MEDIA INPUT INFRASTRUCTURE (V4L/DVB)MAINTAINERS section matched on drivers/media/ · linux-media@vger.kernel.org · Maintained
- Kernel module
- videodev
Check it on the machine
grep -w CONFIG_VIDEO_DEV /boot/config-$(uname -r)Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.
lsmod | grep -w videodevPrints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.
Show whether Debian builds this, per release
Debian builds this, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed.
- bookworm, trixie, forky, sid, bookworm · linux-6.12Mnot built on amd64/cloud-amd64, arm64/cloud-arm64
- M
- a module where it is built at all; some flavours do not build it
- Build switch
- CONFIG_VIDEO_DEV
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages
Signals
- Published
- 2026-09-11 (37 days ago)source
- CVSS
- 7.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.17%, higher than 5.8% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/media
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 5.10.239 | 5.10.270 | 8b998c171ed8 |
| 5.15.186 | 5.15.221 | 3de14b4f681a |
| 6.1.142 | 6.1.188 | 8027f82c0f54 |
| 6.6.95 | 6.6.157 | 2ac009a65d23 |
| 6.12.35 | 6.12.109 | 712ca1cf756d |
| 6.16 | 6.18.50 | aad08b5f67d2 |
| 6.16 | 7.2.4 | ce792b94e038 |
| 6.16 | 7.3 | e7600f5cee5d |
| 5.4.295 | 0 | 0 |
| 6.15.4 | 0 | 0 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4841-1 | 2026-10-17 | bookworm 6.1.190-1 | tracker |
| DLA-4817-1 | 2026-10-04 | bookworm 6.12.111-1~deb12u1 | tracker |
| DSA-6528-1 | 2026-09-29 | trixie 6.12.111-1 | tracker |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:LAttack vector, local
- The double-free is in __video_register_device(), reached from local V4L2 registration such as USB gadget UVC configfs UDC bind (uvc_function_bind → uvc_register_video) and usbfs/sysfs re-probe of USB cameras; dummy_hcd suffices and there is no remote packet path.
- AC:LAttack complexity, low
- A local attacker can retry gadget bind or device re-probe under memory/resource pressure to make device_register() fail and take the put_device() error path; success does not depend on a victim-owned race or uninfluenced layout.
- PR:LPrivileges required, low
- __video_register_device() and uvc_function_bind() perform no capable() check; Android/embedded HALs routinely delegate usb_gadget configfs to non-root, and desktop usbfs/video nodes are typically uaccess/video-group, so init-namespace root is not required.
- UI:NUser interaction, none
- The attacker performs the configfs UDC bind or local re-probe and applies resource pressure themselves; no separate victim mount, file-open, or cable-plug action is required.
- S:UScope, unchanged
- The heap double-free corrupts a kmalloc'd video_device or the parent object freed by vdev->release() inside the same host kernel security authority and does not cross a VM, IOMMU, or sandbox boundary.
- C:HConfidentiality impact, high
- On device_register() failure the buggy put_device() runs v4l2_device_release() which calls vdev->release()/kfree, then callers such as video_device_release() or gspca/uvc probe error paths free the same object again, yielding a UAF disclosure primitive.
- I:HIntegrity impact, high
- The same double-free of struct video_device (or parent driver objects via vdev->release, as in UVC kref_put/uvc_delete and gspca_release) is heap corruption that can be sprayed into an arbitrary write and control-flow hijack.
- A:HAvailability impact, high
- The double-free and premature v4l2_device_release() (including media_devnode_remove() on a still-NULL intf_devnode) oops or panic the kernel, and the attacker can repeat failed registration to force the crash.