CVE-2021-22659: Rockwellautomation Micrologix 1400 Firmware

High severity, CVSS 8.6. EPSS: 1.7% chance of exploitation in the next 30 days.

Rockwell Automation MicroLogix 1400 Version 21.6 and below may allow a remote unauthenticated attacker to send a specially crafted Modbus packet allowing the attacker to retrieve or modify random values in the register. If successfully exploited, this may lead to a buffer overflow resulting in a denial-of-service condition. The FAULT LED will flash RED and communications may be lost. Recovery from denial-of-service condition requires the fault to be cleared by the user.

Affected products

• Rockwellautomation Micrologix 1400 Firmware: up to and including 21.6

Published 2021-03-25. Last modified 2026-06-17.