CVE-2018-7842: Schneider Electric Modicon m340 Firmware

Critical severity, CVSS 9.8. EPSS: 35% chance of exploitation in the next 30 days.

A CWE-290: Authentication Bypass by Spoofing vulnerability exists in all versions of the Modicon M580, Modicon M340, Modicon Quantum, and Modicon Premium which could cause an elevation of privilege by conducting a brute force attack on Modbus parameters sent to the controller.

Affected products

• Schneider Electric Modicon m340 Firmware: any version
• Schneider Electric Modicon m580 Firmware: any version
• Schneider Electric Modicon Premium Firmware: any version
• Schneider Electric Modicon Quantum Firmware: any version

Published 2019-05-22. Last modified 2026-06-17.