Siemens SIMATIC HMI Basic Panels 2nd Generation before WinCC (TIA Portal) 13 SP1 Upd2, SIMATIC HMI Comfort Panels before WinCC (TIA Portal) 13 SP1 Upd2, SIMATIC WinCC Runtime Advanced before WinCC (TIA Portal) 13 SP1 Upd2, SIMATIC WinCC Runtime Professional before WinCC (TIA Portal) 13 SP1 Upd2, SIMATIC HMI Basic Panels 1st Generation (WinCC TIA Portal), SIMATIC HMI Mobile Panel 277 (WinCC TIA Portal), SIMATIC HMI Multi Panels (WinCC TIA Portal), and SIMATIC WinCC 7.x before 7.3 Upd4 allow remote attackers to complete authentication by leveraging knowledge of a password hash without knowledge of the associated password.