CVE-2019-6821: Schneider Electric Modicon m340 Firmware

Medium severity, CVSS 6.5. EPSS: 1.9% chance of exploitation in the next 30 days.

CWE-330: Use of Insufficiently Random Values vulnerability, which could cause the hijacking of the TCP connection when using Ethernet communication in Modicon M580 firmware versions prior to V2.30, and all firmware versions of Modicon M340, Modicon Premium, Modicon Quantum.

Affected products

• Schneider Electric Modicon m340 Firmware: any version
• Schneider Electric Modicon m580 Firmware: before 2.30 (fixed in 2.30)
• Schneider Electric Modicon Premium Firmware: any version
• Schneider Electric Modicon Quantum Firmware: any version

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