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CVE-2026-97575
media: v4l2-ctrls: validate AV1 tile counts
Published 2026-09-25 (24 days ago) by the Linux kernel CNA. Subsystem drivers/media. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-97575 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 | not affected | 6.1.190-1 | Nothing to do. bookworm never shipped the vulnerable code. |
| 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 | 7.2.7-1 | Update the kernel and reboot. Fixed in 7.2.7-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.2.7-1 | Update the kernel and reboot. Fixed in 7.2.7-1. 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 stateless AV1 decoders use tile_info.tile_cols and tile_rows as loop bounds and as indices into the mi_*_starts[] and *_in_sbs_minus_1[] arrays, as the divisor for context_update_tile_id, and their product bounds the per-tile descriptor buffers, but std_validate_compound() does not bound these u8 fields. Reject a V4L2_CTRL_TYPE_AV1_FRAME whose tile_cols or tile_rows exceeds V4L2_AV1_MAX_TILE_COLS / _ROWS, or whose product exceeds V4L2_AV1_MAX_TILE_COUNT. A zero tile count is left to the consuming driver so the zero-initialised control that existing userspace submits is still accepted.
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-ctrls-core.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
- 2026-09-25 (24 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
- 0.16%, higher than 5.2% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- unimportantsource
- 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 |
|---|---|---|
| 6.5 | 6.6.158 | 1afaf85c4990 |
| 6.5 | 6.12.111 | 85df9fc79b07 |
| 6.5 | 6.18.53 | c8891da0186f |
| 6.5 | 7.2.7 | c4c88b5ba856 |
| 6.5 | 7.3 | 439058ced617 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| 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 attacker-controlled tile_info.tile_cols/tile_rows u8s enter the kernel in V4L2_CID_STATELESS_AV1_FRAME via VIDIOC_S_EXT_CTRLS (or the request-fd path through try_set_ext_ctrls_request) on a local /dev/videoN AV1 decoder; validate_av1_frame() in std_validate_compound() is that ioctl's check. No network protocol carries those fields.
- AC:LAttack complexity, low
- The attacker sets tile_cols and tile_rows to any u8 (e.g. 255) in that AV1_FRAME control and queues STREAMON/MEDIA_REQUEST_IOC_QUEUE; vdec_av1_slice_setup_tile() and rockchip_vpu981_av1_dec_set_tile_info() then loop and index on those values deterministically, with no race or victim-side state.
- PR:LPrivileges required, low
- hantro_open() and fops_vcodec_open() have no capable() check; v4l2_prio_check() only compares V4L2 file-handle priority among openers. An unprivileged local user who can open the decoder node (video group, udev uaccess, or Android media-codec UID) is sufficient.
- UI:NUser interaction, none
- The attacking process itself opens the stateless AV1 decoder, submits the crafted AV1_FRAME control, queues buffers, and starts streaming. No victim action such as mounting media or opening a file is required.
- S:UScope, unchanged
- The overflows stay inside the kernel's kzalloc'd vdec_av1_slice_pfc (lat_buf->private_data) and the hantro tile_info coherent DMA buffer in the same kernel security authority. No VM, IOMMU, or sandbox boundary is crossed.
- C:HConfidentiality impact, high
- rockchip_vpu981_av1_dec_set_tile_info() reads group_entry[tile1*tile_cols+tile0] with a product up to 255*255 past the V4L2_AV1_MAX_TILE_COUNT TILE_GROUP_ENTRY array, and indexes height_in_sbs_minus_1[tile1] past its 64-entry field, pulling adjacent kernel heap into the decode path.
- I:HIntegrity impact, high
- vdec_av1_slice_setup_tile() writes tile_cols+1 entries into mi_col_starts[V4L2_AV1_MAX_TILE_COLS+1] on the kzalloc'd pfc before the later product check; rockchip_vpu981_av1_dec_set_tile_info() writes 16 bytes per tile into a 128-slot (AV1_TILE_INFO_SIZE) DMA buffer for up to 255*255 tiles, an attacker-controlled kernel write.
- A:HAvailability impact, high
- Those heap and DMA-buffer overruns walk into unmapped or poisoned memory and produce a kernel oops or KASAN report, and the attacker can repeat the AV1_FRAME request at will.