CVE-2021-39970
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 · uneditedHwPCAssistant has a Improper Input Validation vulnerability.Successful exploitation of this vulnerability may create any file with the system app permission.
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 confidenceHwPCAssistant contains an improper input validation vulnerability that allows attackers to create arbitrary files with system app permissions. This could enable privilege escalation or malicious file placement in protected system directories.
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< 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
- None
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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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Check HarmonyOS versionGo to Settings > About Phone > Version on the Huawei/HarmonyOS device, or use 'getprop ro.build.version.harmonyos' via ADB shellAffected if The version number is below 2.0 (e.g., 1.x versions)
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Verify HwPCAssistant is presentCheck for the HwPCAssistant system app in the application list (Settings > Apps > HwPCAssistant) or via ADB command 'pm list packages | grep hwpc'Affected if The HwPCAssistant package is installed on the device
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Confirm PC connection feature is enabledNavigate to Settings > Huawei > PC Manager or Settings > Connections > Huawei Share/PC Connection to verify if the PC connection service is activeAffected if The HwPCAssistant or PC Manager feature has been used or enabled at least once
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Check for recent file creation activityReview system logs via 'logcat -d | grep -i hwpcassistant' or check audit logs for file creation operations from the HwPCAssistant processAffected if File creation events from HwPCAssistant with elevated (system) permissions appear in the logs
A user is affected if their HarmonyOS version is below 2.0 and the HwPCAssistant component is present and has been enabled on the device.
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.
dbcve · scoped2.0
Implement strict input validation and sanitization for all file creation operations, enforce allowlist-based path validation, and apply least-privilege principles to prevent arbitrary file creation with elevated permissions.
HarmonyOS 2.0
- Check the current HarmonyOS version on the device through Settings > About Phone > Version
- Perform a system update to upgrade to HarmonyOS 2.0 or later through Settings > System & Updates > Software Update
- After the update completes, verify the HwPCAssistant application has been updated to the patched version
- Confirm the vulnerability is remediated by ensuring the path traversal in HwPCAssistant no longer allows arbitrary file creation with system app permissions
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-39970 — 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-2021-39970 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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