dbcve.org
Development SystemApplication · Codesys

CVE-2021-29239

HIGH · 7.8 CVSS v3.1 Published 2021-05-03
Fix available
A fix is available. Upgrade to 3.5.17.0 or later.
See remediation →
80/100
Remediation priority · High
Zero-click

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 · unedited
CODESYS Development System 3 before 3.5.17.0 displays or executes malicious documents or files embedded in libraries without first checking their validity.

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 confidence

CODESYS Development System 3 versions before 3.5.17.0 fail to validate documents or files embedded within library files before displaying or executing them. An attacker could embed malicious content in a crafted library file and trigger execution when a user opens or imports it in the development environment.

MitigationUpgrade CODESYS Development System to version 3.5.17.0 or later. Until patched, avoid opening library files from untrusted sources.

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
Development SystemApplication
Affected:>= 3.0, < 3.5.17.0

CVSS 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
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/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 checks

Work through these to decide whether this CVE applies to you.

  1. Verify CODESYS Development System 3 is installed
    Check for CODESYS Development System 3 installation in Program Files folder or look for the executable (typically named CODESYS.exe or similar)
    Affected if The software is present on the system
  2. Identify the installed version number
    Right-click the CODESYS executable, select Properties, and check the Details tab for the version information. Alternatively, launch the application and navigate to Help > About to view the version.
    Affected if Version is listed as 3.0 or higher but below 3.5.17.0
  3. Confirm the library file handling feature is in use
    The vulnerability affects the opening or importing of library files (typically .library or .libpkg files) within the development environment
    Affected if The user opens, imports, or works with library files in CODESYS Development System 3

If CODESYS Development System 3 version 3.0 or higher but lower than 3.5.17.0 is installed and the user opens or imports library files, the environment is affected by this vulnerability.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Upgrade available Upgrade to 3.5.17.0 or later
Fixed in 3.5.17.0
Interim mitigation

Upgrade CODESYS Development System to version 3.5.17.0 or later. Until patched, avoid opening library files from untrusted sources.

Fix this in Development System Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing4.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,160
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,856.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2021-29239 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-29239 in production — separate from our analysis above.

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.

What this is

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.

What belongs here
  • 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