A vulnerability has been identified in SIMATIC Drive Controller family (All versions < V2.9.2), SIMATIC ET 200SP Open Controller CPU 1515SP PC (incl. SIPLUS variants) (All versions), SIMATIC ET 200SP Open Controller CPU 1515SP PC2 (incl. SIPLUS variants) (All versions < V21.9), SIMATIC S7-1200 CPU family (incl. SIPLUS variants) (All versions < V4.5.0), SIMATIC S7-1500 CPU family (incl. related ET200 CPUs and SIPLUS variants) (All versions < V2.9.2), SIMATIC S7-1500 Software Controller (All versions < V21.9), SIMATIC S7-PLCSIM Advanced (All versions < V4.0), SINUMERIK MC (All versions < V6.21), SINUMERIK ONE (All versions < V6.21). Affected products protect the built-in global private key in a way that cannot be considered sufficient any longer. The key is used for the legacy protection of confidential configuration data and the legacy PG/PC and HMI communication. This could allow attackers to discover the private key of a CPU product family by an offline attack against a single CPU of the family. Attackers could then use this knowledge to extract confidential configuration data from projects that are protected by that key or to perform attacks against legacy PG/PC and HMI communication.