CVE-2021-42707
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 an out-of-bounds write 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 · moderate confidencePLC Editor versions 1.3.8 and prior contains an out-of-bounds write vulnerability in its project file processing functionality. When parsing specially crafted project files, the software writes data beyond the allocated buffer boundaries, leading to memory corruption. This can be exploited to achieve arbitrary code execution by an attacker who can deliver a malicious project file to the victim.
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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Check if PLC Editor is installedLook for the We Con Plc Editor application in the system program files directory, or check the installed programs list via Control Panel or system inventory toolsAffected if We Con Plc Editor is found on the system
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Identify the installed versionRight-click the PLC Editor executable, select Properties, and check the File Version field, or run the application and look for version information in the Help/About menuAffected if The version number is 1.3.8 or lower
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Verify project file handling capabilityCheck if the PLC Editor installation includes project file parsers or load/save functionality by examining the application's supported file extensions in the installation directory or registryAffected if The software supports loading or parsing project files (common extensions include .plc, .proj, or vendor-specific project file formats)
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Inspect recent project file accessReview recent files opened by PLC Editor or check the application's recent files list for any externally-sourced project filesAffected if The user has opened project files, especially from untrusted or external sources
You are affected if We Con Plc Editor version 1.3.8 or lower is installed and the software is used to open or parse project files.
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 PLC Editor to a version beyond 1.3.8 when available. Until then, avoid opening untrusted or externally-sourced project files in PLC Editor, as the vulnerability is triggered during file parsing.
- Consultation6.0 h
- Implementation12.0 h
- Testing8.0 h
- Review / QA6.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-42707 — 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-2021-42707 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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