CVE-2021-39988
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 HwNearbyMain module has a NULL Pointer Dereference vulnerability.Successful exploitation of this vulnerability may cause a process to restart.
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 confidenceA NULL Pointer Dereference vulnerability exists in the HwNearbyMain module, which is part of Huawei's Nearby service functionality. When an attacker triggers the vulnerability by providing specific input that causes a null pointer to be dereferenced, the affected process crashes and restarts, resulting in denial of service.
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
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 checksWork through these to decide whether this CVE applies to you.
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Check HarmonyOS versionNavigate to Settings > About Phone > Version on the Huawei device, or run 'getprop ro.build.version.harmonyos' via ADB shellAffected if The reported version number is less than 2.0 (e.g., 1.x, 1.5.x, etc.)
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Verify HwNearbyMain module presenceCheck for the presence of the HwNearbyMain component in the system. On HarmonyOS devices, this may be found in /system/lib/ or /system/app/ directories, or check via 'pm list packages' for nearby-related packagesAffected if The HwNearbyMain module or nearby-related package is installed on the device
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Confirm Nearby service is enabledGo to Settings > Huawei > Nearby (or Settings > Connections > Nearby) on the device and check if the Nearby service toggle is enabled, or check via device management APIsAffected if The Nearby service functionality is currently turned on or was recently used
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Check for recent crashesReview system logs (logcat) or crash reports for patterns of null pointer dereference errors related to the HwNearbyMain process, or check Settings > Huawei > Troubleshooting > Crash logsAffected if There are recurring crash logs or restart events tied to the HwNearbyMain or nearby service process
The device is affected if it runs HarmonyOS version below 2.0 and has the HwNearbyMain module present with the Nearby service enabled or recently active.
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
Apply the vendor patch for CVE-2021-39988 when available, which should include proper null pointer validation in the HwNearbyMain module before dereferencing pointers.
HarmonyOS 2.0 or later
- 1. Identify all devices or systems running HarmonyOS versions prior to 2.0
- 2. Check the HarmonyOS update catalog or release notes for version 2.0 availability for your specific device model
- 3. Initiate the system update process to upgrade to HarmonyOS 2.0 or later
- 4. Verify the update was successful by checking the system version in Settings > About Device
- 5. Test the HwNearbyMain module functionality to ensure proper operation after upgrade
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
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-39988 — 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-2021-39988 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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