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Modicon M580 Bmep584040 FirmwareOperating system · Schneider Electric

CVE-2020-7542

HIGH · 7.5 CVSS v3.1 Published 2020-12-11
Fix available
A fix is available. Upgrade to 3.20 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

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 · unedited
A CWE-754: Improper Check for Unusual or Exceptional Conditions vulnerability exists in Modicon M580, Modicon M340, Legacy Controllers Modicon Quantum & Modicon Premium (see security notifications for affected versions), that could cause denial of service when a specially crafted Read Physical Memory request over Modbus is sent to the controller.

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 confidence

A CWE-754 improper check for unusual or exceptional conditions vulnerability exists in Schneider Electric Modicon controllers (M580, M340, Quantum, Premium). When a specially crafted Read Physical Memory request over Modbus is sent to the controller, it fails to properly validate the request, leading to a denial of service condition where the controller becomes unresponsive or crashes.

MitigationApply available firmware updates from Schneider Electric's security notifications. If updates are unavailable, implement network segmentation to restrict Modbus access to trusted devices only and monitor for anomalous Read Physical Memory requests.

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
Modicon M580 Bmep584040 FirmwareOperating system
Affected:< 3.20
Modicon M580 Bmep582040 FirmwareOperating system
Affected:< 3.20
Modicon M580 Bmep586040 FirmwareOperating system
Affected:< 3.20
Modicon M580 Bmep585040 FirmwareOperating system
Affected:< 3.20
Modicon M580 Bmep582020 FirmwareOperating system
Affected:< 3.20
Modicon M580 Bmep581020 FirmwareOperating system
Affected:< 3.20
Modicon M580 Bmep584020 FirmwareOperating system
Affected:< 3.20
Modicon M580 Bmep583040 FirmwareOperating system
Affected:< 3.20

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
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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify Modicon controller model
    Locate the controller hardware nameplate or check the device configuration in Unity Pro/Unity XL programming software. Look for model numbers such as Bmep581020, Bmep582020, Bmep582040, Bmep583040, Bmep584020, Bmep584040, Bmep585040, Bmep586040, or other Modicon M580, M340, Quantum, or Premium modules.
    Affected if The controller model is a Modicon M580, M340, Quantum, or Premium series device.
  2. Check firmware version
    Access the controller via Unity Pro/Unity XL programming software, EcoStruxure Control Expert, or the web server interface if available. Navigate to the firmware revision information. Compare the installed firmware version to the affected threshold of < 3.20 for M580 models.
    Affected if The installed firmware version is lower than 3.20 for M580 controllers, or unknown/earlier stable revisions for M340, Quantum, or Premium controllers.
  3. Verify Modbus communication is enabled
    Check the controller configuration in the programming software for Modbus TCP or Modbus Serial communication settings. Confirm whether Modbus protocol stacks (MBTCP, MBSLAVE) are loaded and active in the controller application.
    Affected if Modbus communication is enabled and the controller is configured to accept Modbus requests.
  4. Assess network accessibility of Modbus ports
    Review network segmentation and firewall rules. Determine if the controller Modbus TCP port (typically 502) or Modbus Serial gateway is accessible from network segments other than a trusted engineering workstation VLAN. Use network scanning or review firewall policies.
    Affected if The Modbus service port (502/TCP) is open to untrusted network segments or the device is directly reachable from outside the control system DMZ.

You are affected if you have a Modicon M580, M340, Quantum, or Premium controller with firmware below 3.20 (for M580) that has Modbus communication enabled and is accessible over the network.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Upgrade available Upgrade to 3.20 or later
Fixed in 3.20
Interim mitigation

Apply available firmware updates from Schneider Electric's security notifications. If updates are unavailable, implement network segmentation to restrict Modbus access to trusted devices only and monitor for anomalous Read Physical Memory requests.

Fix this in Modicon M580 Bmep584040 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2020-7542 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
  • 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
  • No spam, self-promotion, credentials, or personal data