CVE-2020-24685: Abb AC500 CPU Firmware

High severity, CVSS 8.6. EPSS: 1.6% chance of exploitation in the next 30 days.

An unauthenticated specially crafted packet sent by an attacker over the network will cause a denial-of-service (DoS) vulnerability. Vulnerability allows attacker to stop the PLC. After stopping (ERR LED flashing red), physical access to the PLC is required in order to restart the application. This issue affects: ABB AC500 V2 products with onboard Ethernet version 2.8.4 and prior versions.

Affected products

• Abb AC500 CPU Firmware: before 2.8.5 (fixed in 2.8.5)

Published 2021-02-09. Last modified 2026-06-17.