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CVE-2026-89887
media: i2c: ov7740: fix use-after-destroy in remove
Published 2026-09-16 (33 days ago) by the Linux kernel CNA. Subsystem drivers/media. Debian urgency: not yet assigned.
Debian does not build this code. The per-release build detail is under "Where it lives" below.
What to do, per Debian release
Debian's own status for CVE-2026-89887 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
The ov7740_remove() function had a severe teardown order bug where it destroyed the driver's mutex before freeing the V4L2 control handler which relies on that mutex, leading to a use-after-destroy kernel panic. Furthermore, the driver explicitly called v4l2_ctrl_handler_free() and mutex_destroy() sequentially, but then called ov7740_free_controls() which invokes both of them a second time, resulting in a double-free. This patch fixes the issue by unregistering the subdevice first, and relying exclusively on ov7740_free_controls() to safely tear down the mutex and control handler in the correct order.
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/i2c/ov7740.c
- What this is
- OMNIVISION OV7740 SENSOR DRIVERMAINTAINERS section matched on drivers/media/i2c/ov7740.c · linux-media@vger.kernel.org · Orphan
- Kernel module
- none to look for. The file would have gone into ov7740, and Debian does not compile it into that module, so finding ov7740 in lsmod would say nothing about this CVE.
Check it on the machine
grep -w CONFIG_VIDEO_OV7740 /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.
Show whether Debian builds this, per release
Debian does not build this code. In 5 releases below, every kernel flavour Debian publishes has the switch off, so the vulnerable file is compiled into no kernel binary Debian ships.
- bookworm, trixie, forky, sid, bookworm · linux-6.12n
- n
- not enabled on any flavour - this release does not build the code
- Build switch
- CONFIG_VIDEO_OV7740
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
- 2026-09-16 (33 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 |
|---|---|---|
| 4.16 | 5.10.270 | 9e4693436c7d |
| 4.16 | 5.15.221 | 81e9765878d3 |
| 4.16 | 6.1.188 | 8a02ee6c1c4e |
| 4.16 | 6.6.157 | 7512838a19af |
| 4.16 | 6.12.110 | 25e2505866c5 |
| 4.16 | 6.18.51 | af81f35e4f42 |
| 4.16 | 7.2.5 | 09453b467990 |
| 4.16 | 7.3 | 5d1b3dea5a44 |
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 UAF is in ov7740_remove() for the onboard OmniVision OV7740 I2C/CSI camera sensor, reached via local I2C teardown (sysfs unbind, i2c delete_device, rmmod) and V4L2 ioctls on /dev/v4l-subdev* (V4L2_SUBDEV_FL_HAS_DEVNODE). No network, Bluetooth, or USB packet path exists.
- AC:LAttack complexity, low
- ov7740_remove() deterministically mutex_destroy()s ov7740->mutex then v4l2_ctrl_handler_free() locks that same mutex and kvfree()s all v4l2_ctrl objects while the subdev is still registered. An attacker holding the node and driving teardown needs no uncontrollable race or rare debug config.
- PR:LPrivileges required, low
- VIDIOC_G/S_CTRL on the subdev node have no capable() check; udev typically grants /dev/v4l-subdev* to the video group or Android camera UID on SAMA5/embedded boards shipping CONFIG_VIDEO_OV7740. Per CNA driver-removal UAF and media i2c unbind precedent this is PR:L, not init-namespace root.
- UI:NUser interaction, none
- The attacker opens the V4L2 subdev node and initiates or coordinates driver teardown themselves (unbind/rmmod/maintenance). CNA driver-removal UAFs score UI:N; no separate victim action such as mounting a filesystem is required.
- S:UScope, unchanged
- The UAF corrupts host kernel heap (struct v4l2_ctrl, v4l2_ctrl_ref, and handler buckets) within the same OS security authority. It is not a VM escape, IOMMU/DMA isolation bypass, or sandbox breakout.
- C:HConfidentiality impact, high
- v4l2_ctrl_handler_free() kvfree()s each v4l2_ctrl while open fds still hold vfh->ctrl_handler and issue VIDIOC_G_CTRL/G_EXT_CTRLS through dangling ctrl lists. Per kernel UAF guidance this enables arbitrary kernel disclosure, so confidentiality is High.
- I:HIntegrity impact, high
- struct v4l2_ctrl embeds ops and type_ops function pointers; VIDIOC_S_CTRL on a sprayed freed object yields control-flow hijack. Kernel UAF guidance scores this High integrity.
- A:HAvailability impact, high
- mutex_lock of the destroyed mutex and later walks of freed ctrl lists after handler_free oops or panic the kernel even when the UAF is not fully turned into a write primitive, so availability is High.