IEC 61850 Communication Stack DoS Vulnerability Advisory

This ABB Cyber Security Advisory details a denial-of-service vulnerability (CVE-2021-27196) in the IEC 61850 communication stack used in several Process Automation products, including PM 876, CI850, CI868, and S+ Operations. The advisory lists affected firmware versions, recommends immediate upgrades to patched versions, and provides mitigation steps for users unable to update.