CVE-2018-7790: Schneider Electric Modicon m221 Firmware

Critical severity, CVSS 9.8. EPSS: 2.5% chance of exploitation in the next 30 days.

An Information Management Error vulnerability exists in Schneider Electric's Modicon M221 product (all references, all versions prior to firmware V1.6.2.0). The vulnerability allows unauthorized users to replay authentication sequences. If an attacker exploits this vulnerability and connects to a Modicon M221, the attacker can upload the original program from the PLC.

Affected products

Published 2018-08-29. Last modified 2026-06-17.