Executive brief
A vulnerability was identified in the Linux kernel's driver for Arm Ethos-U NPUs (Neural Processing Units), which are used to accelerate machine learning tasks. A flaw in how the driver processes command streams allows a local user to trigger an out-of-bounds memory write. This could potentially lead to a system crash or allow an attacker to gain elevated privileges on the affected device.
Technical details
A heap out-of-bounds (OOB) write vulnerability exists in the ethosu_gem_cmdstream_copy_and_validate() function within the Linux kernel's accel/ethosu driver. The root cause is an unchecked index increment when parsing 64-bit command words (where bit 14 is set). While the loop correctly checks bounds for the first word, it fails to re-verify the index after incrementing it to write the second word of a 64-bit command. An attacker with access to the ioctl interface can control both the buffer contents and the size argument, allowing them to write four bytes past the end of a DMA-allocated buffer. This can result in kernel memory corruption, system instability, or local privilege escalation. The issue has been patched by adding a bounds check before the second write.
Affected products
- Linux Linux Kernel 6.19, 7.0.13, 7.1
Timeline
- 2026-06-25: disclosed
- 2026-06-25: advisory