CVE-2018-7761
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 exists in the HTTP request parser in Schneider Electric's Modicon M340, Modicon Premium, Modicon Quantum PLC, BMXNOR0200 which could allow arbitrary code execution.
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 confidenceA buffer overflow vulnerability exists in the HTTP request parser of Schneider Electric Modicon M340, Modicon Premium, Modicon Quantum PLC, and BMXNOR0200 devices. The flaw in parsing HTTP requests can be exploited to achieve arbitrary code execution on the affected PLCs, potentially allowing attackers to take complete control of the device.
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 versionsall versionsall versionsall versionsall versionsall versionsall versionsall 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
- High
CVSS:3.0/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 PLC via the engineering workstation or network and retrieve the exact model number from the device configuration or web interface. Look for identifiers such as BMXNOR0200, BMXNOR0200H, 140cpu65150, 140cpu31110, 140cpu43412u, 140cpu65160, 140cpu65260, or 140cpu65860.Affected if The device model matches any of these identifiers: BMXNOR0200, BMXNOR0200H, 140cpu65150, 140cpu31110, 140cpu43412u, 140cpu65160, 140cpu65260, or 140cpu65860.
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Check if HTTP web server is enabledLog into the PLC web interface (if accessible) or use the engineering software (e.g., Unity Pro or EcoStruxure) to verify whether the embedded web server / HTTP service is enabled in the device configuration settings.Affected if The HTTP web server is enabled and accessible on the PLC.
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Verify firmware versionRetrieve the firmware version from the device via the web interface, engineering software, or SNMP. Compare the installed firmware version against the affected product list.Affected if The device is one of the listed models and is running any firmware version (all versions are affected per the advisory).
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Assess network exposure of HTTP interfaceReview network segmentation and firewall rules to determine if the PLC HTTP port (typically port 80/443) is reachable from untrusted network segments or the internet.Affected if The HTTP interface is exposed to untrusted or external network segments without network isolation.
If the device is a BMXNOR0200 or 140cpu series PLC with HTTP enabled and accessible from the network, the environment is affected by this vulnerability.
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 dataIsolate affected PLCs on dedicated network segments and apply vendor-provided firmware updates. If patches are unavailable, restrict network access to the HTTP interface and monitor for anomalous traffic.
- Consultation12.0 h
- Implementation20.0 h
- Testing16.0 h
- Review / QA8.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-7761 — 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-2018-7761 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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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- 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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