CVE-2020-7536
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-754:Improper Check for Unusual or Exceptional Conditions vulnerability exists in Modicon M340 CPUs (BMXP34* versions prior to V3.30) Modicon M340 Communication Ethernet modules (BMXNOE0100 (H) versions prior to V3.4 BMXNOE0110 (H) versions prior to V6.6 BMXNOR0200H all versions), that could cause the device to be unreachable when modifying network parameters over SNMP.
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-754 improper check for unusual or exceptional conditions vulnerability exists in Schneider Electric Modicon M340 CPUs and Ethernet communication modules. When network parameters are modified over SNMP on affected versions, the device can enter an unrecoverable state and become unreachable, causing a denial of service.
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< 3.4CVSS 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 Modicon M340 device modelLocate the model number printed on the CPU module or Ethernet module (e.g., BMXP341000, BMXP342000, BMXP3420102, Bmxnoe0100)Affected if Model is one of: BMXP341000, BMXP342000, BMXP3420102, BMXP3420102cl, BMXP342020, BMXP3420302, BMXP3420302cl, or Bmxnoe0100
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Check the firmware versionAccess the device via Unity Pro/ProWORX or through the Ethernet module web interface to view the firmware version informationAffected if Firmware version is below 3.30 for BMXP34* models, or below 3.4 for Bmxnoe0100
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Verify SNMP is enabledCheck the SNMP configuration in the device network settings or Ethernet module web interface to confirm SNMP community strings are configured and SNMP access is permittedAffected if SNMP is enabled and accessible from the network segment where the attack would originate
A user is affected if they have a BMXP34* model with firmware below 3.30 or a Bmxnoe0100 with firmware below 3.4, and SNMP is enabled with network access for potential attackers.
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 data3.43.30
Upgrade firmware to vendor-specified versions (BMXP34* to V3.30, BMXNOE0100(H) to V3.4, BMXNOE0110(H) to V6.6). For BMXNOR0200H with no available patch, implement network segmentation and SNMP access controls to reduce attack surface.
- Consultation4.0 h
- Implementation6.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-7536 — 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-2020-7536 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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