CVE-2021-40004
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 cellular module has a vulnerability in permission management. Successful exploitation of this vulnerability may affect data confidentiality.
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 confidenceThis is a permission management vulnerability in cellular module firmware/software. The flaw allows unauthorized access to data due to improper authorization controls in the cellular module, potentially exposing sensitive information to attackers.
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
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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 cellular module in the environmentInventory all hardware components that contain cellular communication capabilities (modems, IoT gateways, M2M devices). Check device documentation or system interfaces for cellular module model information.Affected if The device contains a cellular module, particularly from Huawei.
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Verify HarmonyOS version on cellular moduleAccess the cellular module's administrative interface, firmware management system, or device settings. Look for the HarmonyOS version listing in system information, firmware details, or about/ status pages.Affected if The cellular module runs Huawei HarmonyOS version 2.0 or later is NOT installed (version is below 2.0).
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Confirm the specific cellular module modelRetrieve the cellular module model number through AT commands (e.g., AT+CGMM), system diagnostics, or hardware labeling. Cross-reference with Huawei product documentation to identify the exact module series.Affected if The module is a Huawei cellular module running vulnerable HarmonyOS firmware.
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Check for unauthorized access indicatorsReview cellular module logs, access logs, and authentication records for suspicious access attempts or unauthorized data access events that may indicate exploitation of the permission bypass.Affected if Unexpected access patterns or data exposure events are found in the module's audit logs.
A user is affected if their cellular module device uses Huawei HarmonyOS with a version number less than 2.0, as this represents the vulnerable configuration where improper authorization controls exist in the cellular module firmware.
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 data2.0
Contact the cellular module vendor for specific patch information and apply available firmware updates; implement network segmentation and access controls as compensating measures until a patch is available.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-40004 — 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-2021-40004 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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