CVE-2021-33840
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 server in Luca through 1.1.14 allows remote attackers to cause a denial of service (insertion of many fake records related to COVID-19) because Phone Number data lacks a digital signature.
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 · high confidenceThe Luca server through version 1.1.14 does not validate phone number data with digital signatures, allowing remote attackers to inject large volumes of fake COVID-19 records by spoofing phone number submissions. This lack of data integrity verification enables a denial of service through data pollution.
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<= 1.1.14CVSS 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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Identify Luca server installationLocate any Luca server instances deployed in your environment - this may be on-premise or self-hosted. Consult your infrastructure inventory or deployment documentation.Affected if Luca server is present in your environment
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Determine installed Luca server versionCheck the version of the deployed Luca server instance. Common methods include: querying the server's API endpoint for version info, reviewing deployment manifests, or checking package/version files if you maintain the server.Affected if The installed version is 1.1.14 or lower
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Verify digital signature validation for phone number dataReview the Luca server configuration and code to determine whether phone number submissions are validated with cryptographic digital signatures before acceptance. This may require code review of the data validation layer or consultation with your Luca server documentation.Affected if Phone number data submissions are accepted without requiring valid digital signatures
Your environment is affected if you are running a self-hosted Luca server version 1.1.14 or lower and phone number submissions are processed without digital signature validation.
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 dataImplement cryptographic digital signatures for all phone number data submissions to verify authenticity and integrity before accepting records into the system.
- Consultation6.0 h
- Implementation16.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $9,600.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-33840 — 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-2021-33840 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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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.
- 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