CVE-2019-5074
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 exploitable stack buffer overflow vulnerability exists in the iocheckd service ''I/O-Check'' functionality of WAGO PFC200 Firmware version 03.01.07(13), WAGO PFC200 Firmware version 03.00.39(12) and WAGO PFC100 Firmware version 03.00.39(12). A specially crafted set of packets can cause a stack buffer overflow, resulting in code execution. An attacker can send unauthenticated packets to trigger this vulnerability.
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 confidenceStack buffer overflow vulnerability in the iocheckd service 'I/O-Check' functionality of WAGO PFC200 and PFC100 PLCs allows unauthenticated remote attackers to overflow a stack-based buffer via specially crafted network packets, achieving code execution on affected devices.
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= 03.01.07\(13\)= 03.00.39\(12\)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
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/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 checksWork through these to decide whether this CVE applies to you.
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Identify the device modelAccess the device via SSH, console, or web interface and confirm the model is WAGO PFC200 or PFC100. Check /proc/cpuinfo, the web UI, or use the command '固' or check device documentation.Affected if Device is not a WAGO PFC200 or PFC100 PLC - different models are not affected by this CVE.
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Check the installed firmware versionOn the device, run '固' or access the web interface to view firmware version. Compare against affected versions: PFC200 = 03.01.07(13), PFC100 = 03.00.39(12).Affected if Firmware version exactly matches 03.01.07(13) for PFC200 or 03.00.39(12) for PFC100.
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Verify the iocheckd service is accessibleCheck if port 6626/TCP (typical I/O-Check service port) is open and listening on the device using 'netstat -an' or 'nmap -p 6626 <device IP>'.Affected if The iocheckd service port is exposed and accessible on the network.
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Assess network exposureReview firewall rules, network topology, and device IP assignment. Determine if the device management interface is reachable from untrusted networks.Affected if Device is directly accessible from untrusted networks without firewall segmentation.
Device is affected if it is a WAGO PFC200 running firmware 03.01.07(13) or PFC100 running firmware 03.00.39(12), and the iocheckd service is network-accessible.
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 dataUpdate WAGO PFC100/PFC200 firmware to patched versions; if patches unavailable, isolate devices behind firewalls or network segmentation to limit attack surface, as exploitation requires only unauthenticated network access.
- Consultation6.0 h
- Implementation8.0 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-2019-5074 — 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-2019-5074 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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