IBM PowerVM Hypervisor FW1120.00 through FW1120.01, FW1110.00 through FW1110.31, and FW1060.00 through FW1060.81 is affected by a vulnerability in a hypervisor call interface. An attacker with root access to a guest partition can read a limited amount of hypervisor memory, potentially exposing sensitive data belonging to the hypervisor or other guest partitions hosted on the same system, resulting in a confidentiality impact. The attacker has no control over which memory contents are returned. This vulnerability is of particular concern in multi-tenant environments where guests may run arbitrary OS images.