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CVE-2026-63846
drm/amdgpu/jpeg: set no_user_fence for JPEG v3.0 ring
Published 2026-07-19 (3 months ago) by the Linux kernel CNA. Subsystem drivers/gpu. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-63846 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 | vulnerable | 6.1.190-1 | No fix published anywhere yet, neither in Debian nor upstream for the series bookworm tracks. Watch the Debian tracker page for this CVE. Advisories for bookworm have historically landed a median of 23 days after publication. |
| Debian 13trixie | fixed | 6.12.94-1 | Update the kernel and reboot. Fixed in 6.12.94-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.0.10-1 | Update the kernel and reboot. Fixed in 7.0.10-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.0.10-1 | Update the kernel and reboot. Fixed in 7.0.10-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
JPEG rings do not support 64-bit user fence writes, reject CS submissions with user fences. (cherry picked from commit 4d7d774f100efb5089c86a1fb8c5bf47c63fc9ef)
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/gpu/drm/amd/amdgpu/jpeg_v3_0.c
- What this is
- RADEON and AMDGPU DRM DRIVERSMAINTAINERS section matched on drivers/gpu/drm/amd/ · amd-gfx@lists.freedesktop.org · Supported
- Kernel module
- amdgpu
Check it on the machine
grep -w CONFIG_DRM_AMDGPU /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 amdgpuPrints 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.
- bookwormMnot built on amd64/cloud-amd64, arm64/cloud-arm64, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp
- trixieMnot built on amd64/cloud-amd64, arm64/cloud-arm64, armel/rpi, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, s390x/s390x
- forky, sidMnot built on amd64/cloud-amd64, arm64/cloud-arm64, s390x/s390x
- M
- a module where it is built at all; some flavours do not build it
- Build switch
- CONFIG_DRM_AMDGPU
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
- 2026-07-19 (3 months 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
- 0.18%, higher than 6.6% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/gpu
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 5.9 | 6.6.141 | ee035a9d3eed |
| 5.9 | 6.12.91 | 303da8279f19 |
| 5.9 | 6.18.33 | 5ada37d7f736 |
| 5.9 | 7.0.10 | 48ce00787e3f |
| 5.9 | 7.1 | a2baf12eec41 |
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 vulnerable code is reached only through DRM_IOCTL_AMDGPU_CS on an AMDGPU render node (/dev/dri/renderD*), requiring a local ioctl to submit a command buffer with AMDGPU_CHUNK_ID_FENCE to the JPEG v3.0 decode ring (AMDGPU_HW_IP_VCN_JPEG).
- AC:LAttack complexity, low
- On affected VCN 3.0.x hardware with JPEG v3.0 (e.g. Navi 21/Sienna_Cichlid RX 6000 series), an attacker fully controls CS submission parameters and can reliably trigger the unsupported 64-bit user fence path without races or conditions beyond attacker control.
- PR:LPrivileges required, low
- DRM_IOCTL_AMDGPU_CS is gated by DRM_AUTH|DRM_RENDER_ALLOW, requiring only local access to the render node available to unprivileged users in the render group or equivalent permissions, not root or special capabilities.
- UI:NUser interaction, none
- Exploitation requires no victim interaction beyond the attacker (or their process) opening the render node and submitting crafted GPU command buffers with user fences.
- S:UScope, unchanged
- The impact is confined to the attacker's GPU security context (their process VM and GPU mappings); exploitation does not cross VM, container, or IOMMU boundaries to affect other security authorities.
- C:HConfidentiality impact, high
- The unsupported 64-bit user fence causes the GPU to perform unintended memory writes that can corrupt adjacent GPU-accessible memory, and memory corruption primitives can be leveraged for information disclosure.
- I:HIntegrity impact, high
- The GPU writes a fence sequence number via GPCOM to an attacker-influenced GPU virtual address, providing a controlled write primitive that can corrupt GPU memory and potentially be chained for further exploitation.
- A:HAvailability impact, high
- Malformed fence operations on unsupported hardware can hang or fault the GPU subsystem, requiring a GPU reset and denying availability of graphics/compute workloads.