CVE-2019-6828 Schneider Electric SE CVE debrief

Who should care

OT/ICS operators and engineering teams running Schneider Electric Modicon controllers or EcoStruxure Control Expert should pay attention, especially if Modbus is reachable across plant networks or from untrusted segments. Owners of affected M580, M340, Quantum, and Premium deployments, including end-of-life systems that cannot be patched quickly, should prioritize review.

Technical summary

The source advisory describes an uncaught exception that may be triggered while reading specific coils and registers over Modbus, resulting in a controller denial of service. The supplied CISA record rates the issue as network-reachable with low attack complexity and no privileges or user interaction required, and the stated impact is availability loss rather than confidentiality or integrity compromise. Remediation entries map to firmware releases such as M580 v4.20, M340 v3.60, Quantum v3.60, and Premium v3.20, plus project and network protections.

Defensive priority

High. A remotely reachable DoS in industrial control equipment can interrupt process visibility or control, so patching or compensating controls should be scheduled promptly, with special attention to any controller exposed beyond a tightly controlled OT segment.

Recommended defensive actions

• Update affected firmware to the vendor-fixed versions listed in the advisory, such as M580 SV4.20+, M340 v3.60+, Quantum v3.60+, or Premium v3.20 where available.
• Update EcoStruxure Control Expert to the version specified by Schneider Electric, then rebuild and transfer affected projects so the engineering environment matches the controller firmware.
• Restrict Modbus access by segmenting the network and blocking unauthorized access to TCP/502 with firewalls or equivalent controls.
• Apply the Access Control List guidance in the vendor manuals for the affected controller family.
• Set an application password in project properties and use the secure-communication/IPsec guidance referenced by Schneider Electric where applicable.
• For Quantum and Premium systems that are end of life, plan migration to supported platforms such as the Modicon M580 family.
• Validate controller and project firmware version alignment after changes and test recovery procedures for any availability-sensitive process.

Evidence notes

This debrief is based on the supplied CISA CSAF advisory, the linked Schneider Electric security notice, and the official CVE record. Timing is anchored to the CVE/public advisory publication date of 2019-05-14, not to later source modifications; the revision history shows additional remediation updates through 2020-12. The supplied enrichment marks the issue as not listed in KEV.

Official resources