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AndroidOperating system · Google

CVE-2021-25396

MEDIUM · 6.7 CVSS v3.1 Published 2021-06-11
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
69/100
Remediation priority · Elevated
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
An improper input validation vulnerability in NPU firmware prior to SMR MAY-2021 Release 1 allows arbitrary memory write and code execution.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

An improper input validation vulnerability in NPU (Neural Processing Unit) firmware prior to SMR MAY-2021 Release 1 allows attackers to write to arbitrary memory locations and achieve code execution due to insufficient validation of input data processed by the NPU firmware.

MitigationUpdate NPU firmware to SMR MAY-2021 Release 1 or later. Identify all devices with affected NPU firmware versions and apply the vendor-provided firmware update following manufacturer deployment procedures.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
AndroidOperating system
Affected:= 10.0= 11.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
High
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify Android version
    Check system settings under 'About Phone' > 'Android version' or run 'getprop ro.build.version.release' via ADB
    Affected if The installed Android version is 10.0 or 11.0
  2. Identify NPU firmware version
    Check NPU firmware version via 'getprop ro.npu.version' or inspect /vendor/firmware/ directory for NPU-related firmware files using ADB shell
    Affected if Cannot determine NPU firmware version or version is prior to SMR MAY-2021 Release 1
  3. Confirm NPU hardware presence
    Verify NPU hardware exists on the device by checking /sys/class/npu/ or running 'ls /dev/npu*' via ADB shell
    Affected if NPU device node or hardware is present and accessible
  4. Check NPU driver loaded
    Verify NPU kernel driver is loaded by running 'lsmod | grep npu' or checking /proc/modules via ADB shell
    Affected if NPU driver module is loaded and active

Device is affected if running Android 10.0 or 11.0 with NPU hardware present and NPU firmware version older than SMR MAY-2021 Release 1.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update NPU firmware to SMR MAY-2021 Release 1 or later. Identify all devices with affected NPU firmware versions and apply the vendor-provided firmware update following manufacturer deployment procedures.

Fix this in Android Scoped from the published advisory
  • Consultation8.0 h
  • Implementation16.0 h
  • Testing12.0 h
  • Review / QA6.0 h
42.0 hours of engineering $7,360
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-25396 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data