EUVD-2026-39263
GHSA-jf8x-7724-7vrr
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Requires local access to the NPU accel device node so AV:L/PR:L; the deterministic mask typo makes triggering trivial (AC:L), and a controlled kernel-heap overwrite yields full C/I/A impact.
Primary rating from Vendor (416baaa9-dc9f-4396-8d5f-8c081fb06d67).
CVSS VectorVendor: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Lifecycle Timeline
5DescriptionCVE.org
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.
AnalysisAI
Heap out-of-bounds write in the Linux kernel's Arm Ethos-U NPU accelerator driver (accel/ethosu) lets a local user with access to the NPU device corrupt adjacent kernel heap memory. The command-stream parser masks the IFM region index with 0x7f (max 127) instead of 0x7 (max 7) like every other region assignment, so a crafted NPU_SET_IFM_REGION opcode with param > 7 indexes far past the 8-entry region_size[]/output_region[] arrays, writing up to ~1016 bytes beyond the allocation. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires local access to a system whose kernel has the accel/ethosu (Arm Ethos-U NPU) driver loaded and an accessible accel device node, plus the ability to submit a command stream containing the NPU_SET_IFM_REGION opcode with the region parameter set greater than 7 (8-127). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | Signals are broadly consistent and point to a real but access-gated local privilege-escalation/DoS risk rather than a mass-exploitation event. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | A local user (or a sandboxed/compromised process granted access to the NPU accel device) opens the Ethos-U device node and submits a malicious command stream containing NPU_SET_IFM_REGION with a region parameter between 8 and 127. The parser writes region metadata far beyond region_size[], corrupting adjacent SLUB heap objects, which an attacker can shape to achieve denial of service or, with careful heap grooming, kernel privilege escalation. … |
| Remediation | Upstream fix available (commits 00f547e0dfecf83014fb32bcba587c6b684c1362 and ee7bed779def61ebff1b92b0e851f412176fa416), which replaces the `param & 0x7f` IFM region mask with `param & 0x7` to match the other region assignments; update to a stable kernel that includes these commits (EUVD references patched 7.0.13 and 7.1 lines) - verify against your distribution's backport before deploying. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours: Inventory all systems with Arm Ethos-U NPU accelerators (focus on edge AI inference platforms, ML accelerator appliances, and IoT gateways). …
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Same weakness CWE-125 – Out-of-bounds Read
View allSame technique Buffer Overflow
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External POC / Exploit Code
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