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CVE-2026-89724
media: vicodec: fix out-of-bounds write in FWHT encoder
Published 2026-09-11 (37 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-2026-89724 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
vidioc_s_fmt_vid_out() sizes the encoder CAPTURE buffer from the compressed descriptor pixfmt_fwht, whose sizeimage_mult is 3: coded_w * coded_h * 3 + sizeof(struct fwht_cframe_hdr). fwht_encode_frame() encodes one plane per component, and an incompressible plane takes the FWHT_FRAME_UNENCODED path in encode_plane(), copying the plane verbatim. For a 4-component pixel format all four planes are full resolution (width_div == height_div == 1), so a frame that forces every plane through the unencoded fallback writes sizeof(struct fwht_cframe_hdr) + 4 * coded_w * coded_h bytes, overrunning the plane by coded_w * coded_h, which can result in corruption of adjacent kernel heap memory. Bump pixfmt_fwht.sizeimage_mult from 3 to 4, matching the largest components_num among the supported raw formats, so the capture buffer is always large enough for the unencoded fallback.
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/test-drivers/vicodec/vicodec-core.c
- What this is
- VICODEC VIRTUAL CODEC DRIVERMAINTAINERS section matched on drivers/media/test-drivers/vicodec/* · linux-media@vger.kernel.org · Maintained
- Kernel module
- none to look for. The file would have gone into vicodec, and Debian does not compile it into that module, so finding vicodec in lsmod would say nothing about this CVE.
Check it on the machine
grep -w CONFIG_VIDEO_VICODEC /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_VICODEC
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 |
|---|---|---|
| 5.0 | 5.10.270 | f7ae26c100a6 |
| 5.0 | 5.15.221 | 6ea647e76c44 |
| 5.0 | 6.1.188 | d40838a63f2b |
| 5.0 | 6.6.157 | e21cccc29b84 |
| 5.0 | 6.12.109 | 84cfebf7f422 |
| 5.0 | 6.18.50 | 8c14472431e2 |
| 5.0 | 7.2.4 | b95315ffc66b |
| 5.0 | 7.3 | cf4500ebf6fb |
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 overflow is reached only through local V4L2 ioctls (VIDIOC_S_FMT, VIDIOC_REQBUFS, VIDIOC_QBUF, VIDIOC_STREAMON) on the vicodec stateful-encoder /dev/videoN node; there is no network or adjacent-protocol path into fwht_encode_frame().
- AC:LAttack complexity, low
- An attacker selects a 4-component OUTPUT format (RGBA32/ARGB32 and similar), feeds incompressible planes (and may set QP=1), and starts streaming so every plane takes the FWHT_FRAME_UNENCODED copy path; no race or uncontrolled memory-layout precondition is required.
- PR:LPrivileges required, low
- vicodec_open() and the encoder ioctl path perform no capability checks; any local user who can open the video node (video group or logind/udev uaccess on desktops, Android, and media CI) can trigger the overflow.
- UI:NUser interaction, none
- The attacking process opens the encoder node, sets the 4-component format, queues incompressible buffers, and starts streaming itself; no victim action or cooperation is required.
- S:UScope, unchanged
- The out-of-bounds write corrupts kernel memory in the same security authority as the kernel itself; this is a conventional in-kernel vmalloc/heap overflow, not a VM, IOMMU, or sandbox boundary crossing.
- C:HConfidentiality impact, high
- encode_plane() writes past the vb2 capture plane into adjacent kernel memory, and that heap/vmalloc corruption is leverageable for kernel information disclosure, matching C:H for comparable V4L2 out-of-bounds writes.
- I:HIntegrity impact, high
- This is an out-of-bounds write of attacker-controlled pixel bytes (0xff remapped to 0xfe) of coded_w*coded_h bytes (at least 640x360) past the capture buffer, a classic kernel memory-corruption primitive suitable for control-flow hijacking.
- A:HAvailability impact, high
- Writing hundreds of kilobytes past the allocated capture plane hits a vmalloc guard page or corrupts neighbouring objects, producing a kernel oops or panic that an unprivileged user can re-trigger at will.