CVE-2021-20706
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 · uneditedImproper input validation vulnerability in the WebManager CLUSTERPRO X 4.3 for Windows and earlier, EXPRESSCLUSTER X 4.3 for Windows and earlier, CLUSTERPRO X 4.3 SingleServerSafe for Windows and earlier, EXPRESSCLUSTER X 4.3 SingleServerSafe for Windows and earlier allows attacker to remote file upload via network.
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 confidenceImproper input validation in the WebManager component of CLUSTERPRO/EXPRESSCLUSTER X 4.3 for Windows allows remote attackers to upload arbitrary files via the network. This is a server-side vulnerability that could lead to remote code execution if attackers can upload and execute malicious files.
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>= 1.0, <= 4.3>= 1.0, <= 4.3>= 1.0, <= 4.3>= 1.0, <= 4.3CVSS 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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Verify if WebManager component is installedCheck the installed CLUSTERPRO/EXPRESSCLUSTER X version and confirm WebManager feature is present. On Windows, this is typically available via the CLUSTERPRO or EXPRESSCLUSTER installation and can be verified through Windows Programs and Features or the cluster management tools.Affected if WebManager component is installed and the installed version falls within 1.0 to 4.3 inclusive
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Confirm WebManager network exposureIdentify if the WebManager interface is listening on network ports. Check for processes listening on typical WebManager ports (often 29001, 29004, or similar) using netstat or the Windows netstat command. Verify network binding configuration in WebManager settings.Affected if WebManager is bound to a network-accessible IP/interface rather than localhost only
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Check WebManager file upload functionalityAccess WebManager web interface (typically https://localhost:port or the configured network address) and navigate to file upload or configuration import features. Verify if arbitrary file upload is possible without proper validation.Affected if WebManager accepts file uploads without proper input validation on the server side
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Inspect uploaded files directoryLocate the WebManager upload directory (commonly found in the CLUSTERPRO/EXPRESSCLUSTER installation path under WebManager or similar subdirectories). Check for any unexpected or suspicious files that should not be present.Affected if Suspicious files are found in WebManager directories, particularly executable or script files that were not intentionally placed there
A system is affected if CLUSTERPRO/EXPRESSCLUSTER X version 1.0 through 4.3 is installed with WebManager enabled and exposed to the network, or if unexpected files appear in WebManager directories.
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-supplied patches or updates for CLUSTERPRO/EXPRESSCLUSTER X. If no patch is available, restrict network access to WebManager interface, implement strict input validation on file upload functions, and consider network segmentation.
- Consultation3.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2021-20706 — 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-2021-20706 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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