CVE-2018-20026
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 · uneditedImproper Communication Address Filtering exists in CODESYS V3 products versions prior V3.5.14.0.
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 confidenceImproper Communication Address Filtering in CODESYS V3 products prior to V3.5.14.0 allows potential unauthorized network communication access to the industrial control software, likely enabling remote attackers to send commands or access the runtime environment without proper validation of communication source addresses.
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>= 3.0, < 3.5.14.0>= 3.0, < 3.5.14.0>= 3.0, < 3.5.14.0>= 3.0, < 3.5.14.0>= 3.0, < 3.5.14.0>= 3.0, < 3.5.14.0>= 3.0, < 3.5.14.0>= 3.0, < 3.5.14.0CVSS 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
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
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 installed CODESYS productLocate the CODESYS Control runtime package on the system. Check the product name which will be one of: Codesys Control For Beaglebone, Codesys Control For Empc A/imx6, Codesys Control For Iot2000, Codesys Control For Linux, Codesys Control For Pfc100, Codesys Control For Pfc200, Codesys Control For Raspberry Pi, or Codesys Control Rte. This is typically visible in the CODESYS Development System or in the installed package information on the runtime device.Affected if The installed product matches any of the eight affected product names listed in the CVE.
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Check installed CODESYS versionOpen CODESYS Development System and navigate to the device or check the runtime package version. On Linux-based devices, you may find version information in the package manager or by checking the installed CODESYS Control package directly. Compare the version number against the affected range: >= 3.0 and < 3.5.14.0.Affected if The installed version is 3.0 or higher but lower than 3.5.14.0.
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Verify network communication is enabledCheck if the CODESYS runtime has network communication ports (typically TCP ports 11740, 11741, or similar) open and listening. This can be done using netstat or ss commands: 'netstat -an | grep -E "11740|11741"' or by reviewing the runtime configuration for enabled communication interfaces.Affected if Network communication is enabled and the runtime is listening on network ports, exposing the address filtering vulnerability.
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Check address filtering configurationExamine the CODESYS runtime network configuration settings for any address filtering or access control lists. Look for settings related to AllowedClients, IPFilter, or similar address validation features. In the CODESYS Development System, check the device configuration under Network Adaptation or Communication Settings.Affected if Address filtering is disabled, not configured, or allows unrestricted access (0.0.0.0/0 or similar), indicating the vulnerability is present.
The environment is affected if a CODESYS Control product from the affected list is installed with a version between 3.0 and 3.5.14.0 and has network communication enabled, as the improper address filtering allows unauthorized remote access.
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 data3.5.14.0
Upgrade CODESYS V3 products to version V3.5.14.0 or later to obtain the address filtering fix. For additional defense-in-depth, implement network segmentation to isolate industrial control system devices and restrict communication to authorized IP addresses/subnets.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-20026 — 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-2018-20026 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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