# CVE-2026-53172: accel/ethosu: fix IFM region index out-of-bounds in command stream parser

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Published: 2026-06-25 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 6.19

## Description

In the Linux kernel, the following vulnerability has been resolved: accel/ethosu: fix IFM region index out-of-bounds in command stream parser 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
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## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/ee7bed779def61ebff1b92b0e851f412176fa416
- https://git.kernel.org/stable/c/00f547e0dfecf83014fb32bcba587c6b684c1362

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