AC500 V2 PLC Web Server Denial of Service Advisory

This ABB cyber security advisory details a denial of service vulnerability affecting AC500 V2 programmable logic controllers (PLCs) with onboard Ethernet, specifically models PM554 through PM573. The vulnerability, identified as CVE-2020-24686 with a CVSS v3 base score of 7.5 (High), can be exploited via sustained long URL requests or ICMP ping floods to crash the web visualization component, preventing legitimate user access and remote visibility, though the PLC application execution remains unaffected.