CVE-2018-7791: Schneider Electric Modicon m221 Firmware

Critical severity, CVSS 9.8. EPSS: 1.9% chance of exploitation in the next 30 days.

A Permissions, Privileges, and Access Control 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 overwrite the original password with their password. If an attacker exploits this vulnerability and overwrite the password, the attacker can upload the original program from the PLC.

Affected products

• Schneider Electric Modicon m221 Firmware: before 1.6.2.0 (fixed in 1.6.2.0)

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