CVE-2020-7541
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 CWE-425: Direct Request ('Forced Browsing') vulnerability exists in the Web Server on Modicon M340, Legacy Offers Modicon Quantum and Modicon Premium and associated Communication Modules (see security notification for affected versions), that could cause disclosure of sensitive data when sending a specially crafted request to the controller over HTTP.
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 CWE-425 (Direct Request/Forced Browsing) vulnerability exists in the Web Server component of Modicon M340, Quantum, and Premium PLCs. The web server fails to properly restrict access to sensitive endpoints, allowing unauthenticated attackers to directly access or request sensitive data by sending specially crafted HTTP requests to specific URLs without going through proper authorization flows.
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< 3.30< 3.30< 3.30< 3.30< 3.30< 3.30< 3.30< 3.3CVSS 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
- Low
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/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 the Modicon M340 model numberLocate the PLC model label or query the device via the engineering workstation to confirm the exact model (Bmxp341000, Bmxp342000, Bmxp3420102, Bmxp3420102cl, Bmxp342020, Bmxp3420302, Bmxp3420302cl) or network module (Bmxnoe0100)Affected if The model is one of the listed affected variants
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Check the installed firmware versionAccess the PLC via the engineering software or web interface and retrieve the firmware version. Compare it against the affected version threshold: Modicon M340 models require firmware < 3.30, Bmxnoe0100 requires firmware < 3.3Affected if Firmware version is below 3.30 for Modicon M340 models, or below 3.3 for Bmxnoe0100
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Verify the web server is enabledCheck the PLC or network module configuration via the engineering workstation to confirm the embedded web server feature is active and listening on HTTP portsAffected if The web server component is enabled and accessible on the network
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Test for unauthenticated endpoint accessSend a direct HTTP GET request to known sensitive endpoints (such as /API, /Config, or similar administrative paths) from an unauthorized client without providing any authentication credentialsAffected if The HTTP request returns sensitive data, configuration files, or administrative responses without requiring authentication
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 data3.33.30
Implement proper access control and authentication enforcement on all web server endpoints, combined with network segmentation to restrict HTTP access to authorized personnel and systems only.
- Consultation6.0 h
- Implementation8.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,296.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-7541 — 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-2020-7541 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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