IBM Power Systems Firmware FW1120.00, FW1110.00 through FW1110.30, FW1060.00 through FW1060.80, FW950.00 through FW950.H2, OP940.00 through OP940.a1 (Power9), and OP940.00 - OP940.81 (Power HMC) is affected by a vulnerability in host firmware configuration parsing. An attacker with service-level access to the BMC/FSP can supply specially crafted configuration data, compromising the host firmware boot stage and everything subsequently loaded by it, resulting in a confidentiality, integrity, and availability impact to the managed system.