CVE-2021-30195
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 · uneditedCODESYS V2 runtime system before 2.4.7.55 has Improper Input Validation.
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 confidenceCODESYS V2 runtime system before version 2.4.7.55 contains an improper input validation vulnerability, potentially allowing attackers to inject malicious input that could be processed without proper sanitization, leading to unexpected behavior or code execution.
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< fw08< fw08< fw08< fw15< fw15< fw15< fw15< fw16CVSS 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
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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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Identify Wago 750 series PLC modelCheck the physical device label or query the device management interface for the exact model number (e.g., 750-893, 750-891, 750-890, 750-889, 750-885, 750-882, 750-881, or 750-880)Affected if The device is one of the listed Wago 750 series models
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Determine the installed firmware versionAccess the device management interface, check the device properties in the CODESYS development environment, or query the PLC directly for its firmware revision informationAffected if The exact firmware version can be retrieved and compared
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Compare firmware version against affected thresholdsReference the installed firmware version against the affected ranges: 750-893/891/890 require fw08 or higher, 750-889/885/882/881 require fw15 or higher, 750-880 requires fw16 or higherAffected if The installed firmware version is below the required threshold for your specific model (e.g., below fw08 for 750-893, below fw15 for 750-889, below fw16 for 750-880)
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Verify CODESYS V2 runtime versionCheck the CODESYS runtime information in the PLC properties or runtime system details, noting that the vulnerability is in CODESYS V2 runtime before version 2.4.7.55Affected if The CODESYS V2 runtime version is earlier than 2.4.7.55
You are affected if you are running a Wago 750 series PLC (893, 891, 890, 889, 885, 882, 881, or 880) with firmware below the specified threshold for your model, combined with a CODESYS V2 runtime version prior to 2.4.7.55.
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 CODESYS V2 runtime systems to version 2.4.7.55 or later to patch the vulnerability. Additionally, implement strict input validation controls and network segmentation to limit exposure.
- Consultation6.0 h
- Implementation4.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,144.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-30195 — 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-2021-30195 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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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
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