CVE-2019-18336
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 · uneditedA vulnerability has been identified in SIMATIC S7-300 CPU family (incl. related ET200 CPUs and SIPLUS variants) (All versions < V3.X.17), SIMATIC TDC CP51M1 (All versions < V1.1.8), SIMATIC TDC CPU555 (All versions < V1.1.1), SINUMERIK 840D sl (All versions < V4.8.6), SINUMERIK 840D sl (All versions < V4.94). Specially crafted packets sent to port 102/tcp (Profinet) could cause the affected device to go into defect mode. A restart is required in order to recover the system. Successful exploitation requires an attacker to have network access to port 102/tcp, with no authentication. No user interation is required. At the time of advisory publication no public exploitation of this security vulnerability was known.
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 confidenceDenial of service vulnerability in Siemens SIMATIC S7-300 CPU family, TDC devices, and SINUMERIK 840D sl controllers. Specially crafted Profinet packets sent to port 102/tcp cause the affected device to enter a defect mode, requiring a restart to recover. Exploitation requires network access to port 102/tcp with no authentication or user interaction needed.
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< 3.3.17< 3.3.17< 3.3.17< 3.3.17< 3.3.17< 3.3.17< 3.3.17< 3.3.17CVSS 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 the SIMATIC S7-300 CPU modelAccess the device via TIA Portal, STEP 7, or the device's web interface to determine the exact CPU model number (e.g., CPU 312 IFM, CPU 313, CPU 314, CPU 315, CPU 315-2 DP, CPU 316-2 DP)Affected if The model is one of the affected S7-300 CPU variants listed in the CVE (312 Ifm, 313, 314, 314 Ifm, 315, 315 2 Dp, 316 2 Dp)
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Check the installed firmware versionRetrieve the firmware version through TIA Portal, STEP 7, or the device's diagnostic functions. Compare the version number to 3.3.17Affected if The firmware version is lower than 3.3.17
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Verify network exposure of port 102/tcpScan the network or check firewall rules to determine if port 102/tcp (Profibus/Profinet communication) is accessible from untrusted networksAffected if Port 102/tcp is exposed to untrusted network segments or the internet
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Confirm the device is a TDC or SINUMERIK 840D sl if not S7-300If the device is not an S7-300 CPU but is a TDC or SINUMERIK 840D sl controller, check its firmware version through the respective engineering softwareAffected if The device is a TDC or SINUMERIK 840D sl controller with an affected firmware version
Your environment is affected if you have a SIMATIC S7-300 CPU (or TDC/SINUMERIK 840D sl) with firmware below 3.3.17 that has port 102/tcp accessible from an untrusted network.
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 data3.3.17
Restrict network access to port 102/tcp using firewalls or network segmentation to trusted IP addresses only. Apply vendor-supplied patches for affected product versions when available.
- Consultation6.0 h
- Implementation12.0 h
- Testing6.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-18336 — 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-2019-18336 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
- No weaponised exploit code, or anything meant to cause harm
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