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CVE-2026-97576
media: v4l2-ctrls: validate HEVC tile counts
Published 2026-09-25 (24 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-2026-97576 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 | 7.2.7-1 | 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 HEVC decoders read num_tile_columns_minus1 + 1 entries from column_width_minus1[] and num_tile_rows_minus1 + 1 from row_height_minus1[] and use them as tile-loop bounds, but std_validate_compound() does not bound these u8 counts. Reject a V4L2_CTRL_TYPE_HEVC_PPS with tiling enabled whose tile counts exceed the uAPI array capacity, mirroring the existing compound-control range checks.
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
- 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 |
|---|---|---|
| 5.5 | 5.15.222 | 9c0a718e24d4 |
| 5.5 | 6.1.189 | 975e01804889 |
| 5.5 | 6.6.158 | 724915535558 |
| 5.5 | 6.12.111 | 400cd78a63cc |
| 5.5 | 6.18.53 | c7b1ef6dc57f |
| 5.5 | 7.2.7 | ba1023d3a6d5 |
| 5.5 | 7.3 | dc694a9929f7 |
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 attacker-controlled bytes are num_tile_columns_minus1, num_tile_rows_minus1 and column_width_minus1[]/row_height_minus1[] in struct v4l2_ctrl_hevc_pps, copied from userspace by VIDIOC_S_EXT_CTRLS through v4l_s_ext_ctrls → v4l2_s_ext_ctrls → user_to_new into std_validate_compound(); no network protocol carries those fields.
- AC:LAttack complexity, low
- Setting V4L2_HEVC_PPS_FLAG_TILES_ENABLED with num_tile_columns_minus1>=20 or num_tile_rows_minus1>=22 is enough; the next decode job (hantro_g2_hevc_dec_run→prepare_tile_info_buffer, rkvdec assemble_hw_pps→compute_tiles_non_uniform, or cedrus_h265_setup→cedrus_h265_write_tiles) uses those u8 counts as loop bounds with no race or hardware-fault precondition.
- PR:LPrivileges required, low
- rkvdec_open(), hantro_open() and cedrus_open() perform no capable() check; v4l2_open only requires opening the decoder /dev/videoN. On Rockchip, Allwinner and Hantro devices that node is granted to unprivileged video-group or Android media-client users, not init-namespace root.
- UI:NUser interaction, none
- The attacking process opens the HEVC decoder itself, issues VIDIOC_S_EXT_CTRLS with the crafted V4L2_CTRL_TYPE_HEVC_PPS, then QBUF/STREAMON via the request API. No separate victim mount, file-open, or playback action is required.
- S:UScope, unchanged
- The overflows remain in kernel stack (vdpu383 assemble_hw_pps column_width[22]), hantro tile_sizes DMA memory, and the rkvdec param_set PPS packet. This is kernel memory corruption under the same security authority, not a VM, IOMMU, or sandbox escape.
- C:HConfidentiality impact, high
- cedrus_h265_write_tiles() and compute_tiles_non_uniform() index column_width_minus1[20] and row_height_minus1[22] with a u8 count up to 255, reading past the v4l2_ctrl_hevc_pps object into adjacent kernel heap that is then copied into stack and DMA tile buffers.
- I:HIntegrity impact, high
- compute_tiles_non_uniform() writes attacker-chosen column_width_minus1[i]+1 values past stack arrays column_width[20/22]; prepare_tile_info_buffer() writes up to 256x256 u16 pairs into a 20x22 tile_sizes DMA buffer; rkvdec_set_bw_field() stores COLUMN_WIDTH(i) past the 80-byte PPS packet.
- A:HAvailability impact, high
- The stack smash of column_width/row_height, the tile_sizes DMA overflow, and rkvdec_set_bw_field() writes past param_set can walk into unmapped or poisoned memory and oops the kernel, and can wedge the HEVC decoder hardware. The trigger is repeatable at will.