CVE-2021-42705
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 · uneditedPLC Editor Versions 1.3.8 and prior is vulnerable to a stack-based buffer overflow while processing project files, which may allow an attacker to execute arbitrary code.
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 PLC Editor versions 1.3.8 and prior contains a stack-based buffer overflow vulnerability that occurs when parsing project files. The application fails to properly validate the size of input data before copying it into a fixed-size stack buffer, allowing an attacker to overwrite adjacent memory and potentially execute arbitrary code by supplying a specially crafted malicious project file.
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<= 1.3.8CVSS 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
- Local
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/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.
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Locate the We Con Plc Editor installationSearch for the executable file (typically named 'WeConPlcEditor.exe' or similar) in common installation directories such as C:\Program Files\WeCon or C:\Program Files (x86)\WeCon, or use the system search feature to find files matching 'PlcEditor' or 'WeCon'Affected if The application executable exists on the system
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Determine the installed versionRight-click the executable file, select Properties, and view the Details tab to read the File Version or Product Version field. Alternatively, open the application and check Help > About or the application title bar for version informationAffected if The reported version number is 1.3.8 or lower (for example, 1.3.7, 1.3.6, 1.3.5, etc.)
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Identify project file handlingObserve whether the application is used to open, import, or parse project files with extensions such as .wcp, .plc, .project, or similar proprietary formats associated with We Con Plc EditorAffected if The application processes or has processed project files from external or untrusted sources
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Confirm vulnerability trigger conditionVerify that the system has the PLC Editor installed and that users routinely load project files into the application, as the buffer overflow occurs specifically during project file parsingAffected if Users load project files into the We Con Plc Editor version 1.3.8 or prior
A system is affected if We Con Plc Editor version 1.3.8 or prior is installed and is used to parse project files, as the stack-based buffer overflow triggers when processing specially crafted project file input.
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 dataUpdate to a version beyond 1.3.8 when available. Until then, implement input validation and bounds checking on all project file parsing routines, and restrict the handling of untrusted project files to sandboxed or isolated environments.
- Consultation8.0 h
- Implementation16.0 h
- Testing12.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-42705 — 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-2021-42705 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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- Version or environment caveats, and links to real fixes
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