Authentication flaw

A vulnerability has been identified in SIMATIC HMI Comfort Panels (incl. SIPLUS variants) (All versions < V16 Update 3a), SIMATIC HMI KTP Mobile Panels (All versions < V16 Update 3a), SINAMICS GH150 (All versions), SINAMICS GL150 (with option X30) (All versions), SINAMICS GM150 (with option X30) (All versions), SINAMICS SH150 (All versions), SINAMICS SL150 (All versions), SINAMICS SM120 (All versions), SINAMICS SM150 (All versions), SINAMICS SM150i (All versions). Affected devices with enabled telnet service do not require authentication for this service. This could allow a remote attacker to gain full access to the device. (ZDI-CAN-12046)