CVE-2021-46839
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 · uneditedThe HW_KEYMASTER module has a vulnerability of missing bounds check on length.Successful exploitation of this vulnerability may cause malicious construction of data, which results in out-of-bounds access.
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 confidenceThe HW_KEYMASTER module in Android contains a missing bounds check on length parameters, allowing attackers to craft malicious data that triggers out-of-bounds memory access. This hardware security module handles cryptographic key operations, making the vulnerability particularly severe as it could allow privilege escalation or cryptographic key compromise.
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= 11.0.1= 12.0.0= 2.0CVSS 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
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
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 checksWork through these to decide whether this CVE applies to you.
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Identify device vendor and modelCheck if the device is a Huawei device by viewing system information or running 'getprop ro.product.manufacturer' and 'getprop ro.product.model' in ADB shellAffected if Device is not a Huawei product - this vulnerability only affects Huawei devices with HW_KEYMASTER
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Determine installed EMUI versionNavigate to Settings > About Phone > Version on Huawei devices, or run 'getprop ro.build.version.emui' in ADB shellAffected if Version displays exactly 11.0.1 or 12.0.0 - these are the affected EMUI versions
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Determine installed HarmonyOS versionNavigate to Settings > About Phone > Version on Huawei devices, or run 'getprop ro.build.version.harmonyos' in ADB shellAffected if Version displays exactly 2.0 - this is the affected HarmonyOS version
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Verify HW_KEYMASTER module presenceCheck if the device uses HW_KEYMASTER for key operations - inspect /vendor/lib/hw/ or /system/lib/hw/ for keymaster*.so files, or review TrustZone/tee logsAffected if HW_KEYMASTER module is present and active on the device - the vulnerability exists within this hardware security module component
A user is affected if they have a Huawei device running EMUI version 11.0.1, EMUI version 12.0.0, or HarmonyOS version 2.0 with an active HW_KEYMASTER module.
Generated from the published advisory. Verify against your own configuration.
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 dataApply vendor-provided security patches or firmware updates for the HW_KEYMASTER component. As a compensating control, restrict access to trusted execution environments and monitor for anomalous keymaster operations.
- Consultation12.0 h
- Implementation8.0 h
- Testing16.0 h
- Review / QA8.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $12,288.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-46839 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-46839 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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
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