CVE-2022-37301
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-191: Integer Underflow (Wrap or Wraparound) vulnerability exists that could cause a denial of service of the controller due to memory access violations when using the Modbus TCP protocol. Affected products: Modicon M340 CPU (part numbers BMXP34*)(V3.40 and prior), Modicon M580 CPU (part numbers BMEP* and BMEH*)(V3.22 and prior), Legacy Modicon Quantum/Premium(All Versions), Modicon Momentum MDI (171CBU*)(All Versions), Modicon MC80 (BMKC80)(V1.7 and prior)
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 · moderate confidenceInteger underflow vulnerability in the Modbus TCP protocol implementation of Schneider Electric Modicon PLCs allows remote attackers to cause memory access violations, resulting in denial of service of the controller.
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< 3.50< 3.50< 4.01< 4.01< 4.01< 4.01< 4.01< 4.01CVSS 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 PLC model and seriesLocate the physical PLC hardware or consult engineering documentation to determine the exact Modicon model number (e.g., Bmx P34 2010, Bmeh582040)Affected if The model is one of the affected variants listed in the CVE
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Determine installed firmware versionAccess the PLC through Schneider Electric programming software (Unity Pro for M340 or EcoStruxure Control Expert for M580) and navigate to the firmware version information, or check the PLC online diagnosticsAffected if The firmware version is below 3.50 for M340 models or below 4.01 for M580 models
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Verify Modbus TCP is enabledCheck the PLC configuration in the programming software under communication settings or web server configuration to confirm Modbus TCP protocol stack is activeAffected if Modbus TCP is enabled and configured on the PLC
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Check network exposure of Modbus TCP portReview firewall rules, network segmentation, and access control lists to determine if port 502 (Modbus TCP) is accessible from untrusted networksAffected if Port 502 is exposed to untrusted or external network segments
The environment is affected if a Modicon M340 or M580 PLC with an affected model number is running firmware below the safe version threshold AND has Modbus TCP enabled and 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.
dbcve · scoped3.504.01
Upgrade firmware to patched versions (M340 V3.41+, M580 V3.23+, MC80 V1.8+). For legacy products without updates (Quantum/Premium, Momentum), implement network segmentation and restrict Modbus TCP access to trusted IP addresses only.
Modicon M340: Firmware version 3.50 or later; Modicon M580: Firmware version 4.01 or later
- 1. Identify the exact model number and current firmware version of your Modicon controller (M340 or M580 series)
- 2. Backup the controller configuration and program using Schneider Electric's backup tools
- 3. Download the firmware update from Schneider Electric's official website (www.se.com) or through their customer support portal
- 4. For Modicon M340 (BMXP34* series): Upgrade firmware to version 3.50 or later
- 5. For Modicon M580 (BMEP* or BMEH* series): Upgrade firmware to version 4.01 or later
- 6. Apply the firmware update using Schneider Electric's recommended upgrade procedure (typically via Unity Pro or EcoStruxure Control Expert programming software)
- 7. After upgrade, verify the controller operates normally and test Modbus TCP functionality
- 8. Confirm the new firmware version matches the fixed release (3.50 for M340, 4.01 for M580)
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation8.0 h
- Implementation12.0 h
- Testing16.0 h
- Review / QA8.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2022-37301 — 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-2022-37301 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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