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CVE-2026-53172
accel/ethosu: fix IFM region index out-of-bounds in command stream parser
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-2026-53172 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
NPU_SET_IFM_REGION extracts the region index with param & 0x7f, giving a maximum value of 127. However region_size[] and output_region[] in struct ethosu_validated_cmdstream_info are both sized to NPU_BASEP_REGION_MAX (8), giving valid indices [0..7]. Every other region assignment in the same switch uses param & 0x7: NPU_SET_OFM_REGION: st.ofm.region = param & 0x7; NPU_SET_IFM2_REGION: st.ifm2.region = param & 0x7; NPU_SET_WEIGHT_REGION: st.weight[0].region = param & 0x7; NPU_SET_SCALE_REGION: st.scale[0].region = param & 0x7; The 0x7f mask on IFM is inconsistent and appears to be a typo. feat_matrix_length() and calc_sizes() use the region index directly as an array subscript into the kzalloc'd info struct: info->region_size[fm->region] = max(...); A userspace caller supplying NPU_SET_IFM_REGION with param > 7 causes a write up to 127*8 = 1016 bytes past the start of region_size[], corrupting adjacent kernel heap data. Fix by applying the same & 0x7 mask used by all other region assignments.
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
- 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
- 0.12%, higher than 1.7% 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 | ee7bed779def |
| 6.19 | 7.1 | 00f547e0dfec |
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 parser is reached through the local DRM accel ioctl DRM_IOCTL_ETHOSU_CMDSTREAM_BO_CREATE on /dev/accel/accel*, with the command stream supplied from a userspace pointer.
- AC:LAttack complexity, low
- A crafted command stream can directly set an IFM region index above 7 and then trigger size calculation; no race or condition outside attacker control is required.
- PR:LPrivileges required, low
- The attacker needs local access to the Ethos-U accel device node as an unprivileged userspace client, but the ioctl has no CAP_SYS_ADMIN, DRM_MASTER, or DRM_AUTH gate.
- UI:NUser interaction, none
- No victim action is required beyond the attacker issuing the ioctl with a malformed command stream.
- S:UScope, unchanged
- The bug is standard kernel heap memory corruption reachable from a local kernel device interface and does not cross a VM, IOMMU, or separate security authority boundary.
- C:HConfidentiality impact, high
- The out-of-bounds region_size access performs an 8-byte heap read during max() and memory corruption can plausibly be leveraged for kernel information disclosure.
- I:HIntegrity impact, high
- The bug performs an out-of-bounds 8-byte heap write up to roughly 1KB beyond the allocated validation info object with attacker-influenced command stream values.
- A:HAvailability impact, high
- The same out-of-bounds heap corruption can readily crash or destabilize the kernel, and repeated local triggering is straightforward.