CVE-2021-20653
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 · uneditedCalsos CSDJ (CSDJ-B 01.08.00 and earlier, CSDJ-H 01.08.00 and earlier, CSDJ-D 01.08.00 and earlier, and CSDJ-A 03.08.00 and earlier) allows remote attackers to bypass access restriction and to obtain unauthorized historical data without access privileges via unspecified vectors.
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 confidenceCalsos CSDJ devices (multiple models including CSDJ-B, CSDJ-H, CSDJ-D, and CSDJ-A) have an access control bypass vulnerability allowing remote unauthenticated attackers to retrieve historical data without proper authorization. The vulnerability is exploitable remotely via unspecified vectors and affects versions up to 01.08.00 (and 03.08.00 for CSDJ-A).
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<= 01.08.00<= 01.08.00<= 01.08.00<= 03.08.00CVSS 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
- Low
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/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 Calsos CSDJ devices on the networkInventory network devices and identify any CSDJ-B, CSDJ-H, CSDJ-D, or CSDJ-A models by checking device banners, MAC OUI, or management interfacesAffected if Any CSDJ device (model B, H, D, or A) is present on the network
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Determine firmware version on CSDJ devicesAccess the device management interface or use SNMP/sysinfo queries to retrieve the installed firmware versionAffected if The firmware version is 01.08.00 or lower for CSDJ-B/H/D, or 03.08.00 or lower for CSDJ-A
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Verify historical data endpoint accessibilityAttempt to access the historical data API or web endpoint (commonly /history, /data, or similar) using a web browser or curl without providing authentication credentialsAffected if Historical data is returned without requiring login or session authentication
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Check device network exposureReview firewall rules and network segmentation to determine if the CSDJ device management interface is directly accessible from untrusted networks or the internetAffected if The device is exposed directly to untrusted networks without firewall protection
A defender is affected if they have any CSDJ-B, CSDJ-H, CSDJ-D, or CSDJ-A device running firmware at or below 01.08.00 (B/H/D) or 03.08.00 (A), and that device can be reached remotely to exploit the unauthenticated historical data access.
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 firmware updates to address the access control bypass; ensure affected devices are not directly exposed to untrusted networks and consider network segmentation as a compensating control until patches are applied.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA3.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-20653 — 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-2021-20653 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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