CVE-2021-20703
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 · uneditedBuffer overflow vulnerability in the Transaction Server 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 code execution via a 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 · moderate confidenceA buffer overflow vulnerability exists in the Transaction Server component of CLUSTERPRO/EXPRESSCLUSTER X 4.3 for Windows and earlier versions. The vulnerability allows remote attackers to achieve code execution by sending specially crafted network requests that overflow a buffer, potentially giving them full control over the affected system.
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
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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.
-
Verify Clusterpro or Expresscluster installationLocate the Clusterpro or Expresscluster installation directory on the system, typically found under Program Files or Program Files (x86), or check Windows Registry for installed NEC cluster software under HKLM\Software\NEC or HKLM\Software\Wow6432Node\NECAffected if The software is found to be installed on the system
-
Determine installed versionLocate the version information file or executable within the installation directory, or check the Windows Registry entry for the installed version number of Clusterpro X or Expresscluster XAffected if The version number is 4.3 or earlier (including all versions from 1.0 through 4.3)
-
Confirm Transaction Server component is presentCheck the services list in Windows Services console (services.msc) or the configuration files within the installation directory for a service or component named 'Transaction Server' or similarAffected if The Transaction Server component is installed and present on the system
-
Verify Transaction Server is running or enabledCheck if the Transaction Server service is in a Running state via Windows Services console, or check the cluster configuration to determine if Transaction Server is configured as an active resourceAffected if The Transaction Server service is enabled and running on the affected version
If Clusterpro X or Expresscluster X versions 1.0 through 4.3 are installed with the Transaction Server component enabled, the environment is affected by this vulnerability.
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 the vendor-provided patch or upgrade to a version beyond 4.3. Since this is a critical RCE vulnerability, prioritize immediate deployment and consider network segmentation to limit exposure until the patch can be applied.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-20703 — 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-2021-20703 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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