CVE-2025-41700
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 · uneditedAn unauthenticated attacker can trick a local user into executing arbitrary code by opening a deliberately manipulated CODESYS project file with a CODESYS development system. This arbitrary code is executed in the user context.
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 confidenceAn unauthenticated attacker can create a malicious CODESYS project file that, when opened by a local user in the CODESYS development environment, executes arbitrary code in the user's security context. The attacker cannot directly execute code but relies on tricking a legitimate user to open the crafted 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< 3.5.21.40CVSS 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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Identify CODESYS installationLocate the CODESYS installation on the system - typically installed in Program Files (x86) or Program Files under 3S-Cozy or similar. Check for the presence of CODESYS executable files.Affected if CODESYS development environment is installed on the system
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Determine installed CODESYS versionOpen CODESYS and navigate to the Help menu, then select About CODESYS. Alternatively, right-click the CODESYS executable, select Properties, and check the Version tab for the product version.Affected if The displayed version number is less than 3.5.21.40
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Verify project file handling capabilityConfirm that the CODESYS installation allows opening project files (.projectpkg, .project, .library files). This is a default enabled feature in the development environment.Affected if Users can open CODESYS project files from any location
If the installed CODESYS version is below 3.5.21.40 and users have the ability to open project files, the environment is vulnerable to arbitrary code execution via malicious 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.
dbcve · scoped3.5.21.40
Apply vendor patches for CODESYS when available; until then, educate users to avoid opening project files from untrusted sources and consider application whitelisting to restrict code execution from unexpected locations.
CODESYS version 3.5.21.40 or later
- 1. Determine the current installed CODESYS version by opening the CODESYS development system and navigating to Help > About CODESYS
- 2. If the installed version is below 3.5.21.40, download CODESYS version 3.5.21.40 or later from the official CODESYS download page
- 3. Close all running CODESYS instances before upgrading
- 4. Run the installer with administrator privileges
- 5. Follow the installation wizard prompts to complete the upgrade
- 6. After installation, verify the new version by checking Help > About CODESYS
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation3.0 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 $3,440.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-41700 — 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-2025-41700 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
- No spam, self-promotion, credentials, or personal data