CVE-2017-16726
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 · uneditedBeckhoff TwinCAT supports communication over ADS. ADS is a protocol for industrial automation in protected environments. ADS has not been designed to achieve security purposes and therefore does not include any encryption algorithms because of their negative effect on performance and throughput. An attacker can forge arbitrary ADS packets when legitimate ADS traffic is observable.
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 confidenceBeckhoff TwinCAT uses the ADS protocol for industrial automation communication, which was designed for performance rather than security and lacks any encryption. An attacker who can observe legitimate ADS traffic can forge arbitrary ADS packets due to the absence of authentication or integrity mechanisms.
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 dataall versionsCVSS 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
- High
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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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Confirm TwinCAT installationCheck for TwinCAT components in Program Files or review installed software list. Look for TwinCAT 2 or TwinCAT 3 directories and services.Affected if TwinCAT software is present on the system
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Identify ADS protocol usageReview TwinCAT configuration files (typically with .tsm, .tpy, or .xti extensions) for ADS router settings. Check if ADS ports (typically 48898/tcp, 48899/tcp) are configured in the ADS router.Affected if ADS protocol is enabled and configured for communication between TwinCAT components or with external devices
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Verify network exposure of ADS portsUse netstat or similar tooling to check if ADS ports (48898, 48899) are listening on external interfaces or accessible from non-localhost IP addresses.Affected if ADS ports are bound to non-localhost interfaces or accessible from untrusted network segments
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Assess network segmentationReview network topology and firewall rules to determine whether the TwinCAT system shares network segments with untrusted devices or is reachable from external networks.Affected if TwinCAT ADS communication traverses untrusted or shared network segments where traffic observation is possible
User is affected if TwinCAT with ADS protocol is installed and the ADS ports are accessible from network segments where an attacker could observe traffic and inject forged packets.
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 dataImplement network segmentation to isolate TwinCAT systems from untrusted networks, and consider deploying VPN tunnels or compensating controls around ADS communications since the protocol itself cannot be modified to add encryption.
- Consultation8.0 h
- Implementation24.0 h
- Testing12.0 h
- Review / QA8.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2017-16726 — 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-2017-16726 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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