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CVE-2026-53171
accel/ethosu: fix arithmetic issues in dma_length()
Published 2026-06-25 (4 months ago) by the Linux kernel CNA. Subsystem drivers/accel. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-53171 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 | not affected | 6.12.113-1 | Nothing to do. trixie never shipped the vulnerable code. |
| Debian 14forky | fixed | 7.0.13-1 | Update the kernel and reboot. Fixed in 7.0.13-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.0.13-1 | Update the kernel and reboot. Fixed in 7.0.13-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
dma_length() derives DMA region usage from command stream values and updates region_size[]: len = ((len + stride[0]) * size0 + stride[1]) * size1 region_size[region] = max(..., len + dma->offset) Several arithmetic issues can corrupt the derived region size: - signed stride values may underflow when added to len - intermediate multiplications may overflow - len + dma->offset may overflow during region_size updates - dma_length() error returns were not validated by the caller region_size[] is later used by ethosu_job.c to validate command stream accesses against GEM buffer sizes. Arithmetic wraparound can therefore under-report region usage and bypass the bounds validation. Fix by validating signed additions, using overflow helpers for multiplications and offset updates, and propagating dma_length() failures to the caller.
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/accel/ethosu/ethosu_gem.c
- What this is
- ARM ETHOS-U NPU DRIVERMAINTAINERS section matched on drivers/accel/ethosu/ · dri-devel@lists.freedesktop.org · Supported
Check it on the machine
grep -wE 'CONFIG_DRM_ACCEL|CONFIG_DRM_ACCEL_ARM_ETHOSU' /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 2 releases. The build rule could not be established for 2 releases, so nothing is claimed about those.
- bookworm, trixie?
- forky, sidn
- ?
- not established - no Makefile entry for the affected file
- n
- not enabled on any flavour - this release does not build the code
Where a release above reads "not established", no build rule for the affected file was found in that release's kernel tree. That is a gap in this lookup, not a finding that the code is absent.
- Build switches
- CONFIG_DRM_ACCEL, CONFIG_DRM_ACCEL_ARM_ETHOSU
- Reads as
- all on means the file is compiled; any one off means it is not.
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
- 2026-06-25 (4 months ago)source
- CVSS
- 8.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.13%, higher than 2.2% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- unimportantsource
- Subsystem
- drivers/accel
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 6.19 | 7.0.13 | 6bb73845d185 |
| 6.19 | 7.1 | ee6d9b6e5162 |
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 path is reached through local DRM accel ioctls on the Ethos-U device, via user-supplied command stream creation and job submission.
- AC:LAttack complexity, low
- The attacker controls the command stream fields that trigger the arithmetic wraparound, and no race or external state is required beyond access to an affected Ethos-U device.
- PR:LPrivileges required, low
- No kernel capability check is present on the relevant driver ioctls, but exploitation requires a local unprivileged process able to open the accel device node.
- UI:NUser interaction, none
- After local device access, the attacker can create buffers and submit the malicious command stream directly without victim interaction.
- S:CScope, changed
- The validation bypass can let NPU DMA access memory outside the intended GEM buffer, crossing the intended DMA/object isolation boundary and potentially affecting kernel or other-process memory.
- C:HConfidentiality impact, high
- An out-of-bounds DMA source can copy memory outside the attacker’s buffer into an attacker-readable destination buffer, giving a plausible high-impact memory disclosure primitive.
- I:HIntegrity impact, high
- An out-of-bounds DMA destination can write outside the validated GEM buffer, giving a plausible high-impact memory corruption primitive.
- A:HAvailability impact, high
- Out-of-bounds DMA can corrupt system memory or trigger bus/device faults and scheduler resets, with a plausible kernel crash or system-level denial of service.