A vulnerability has been identified in SIMATIC HMI Comfort Panels (incl. SIPLUS variants) (All versions < V17 Update 4), SIMATIC HMI KTP Mobile Panels (All versions < V17 Update 4), SIMATIC HMI KTP1200 Basic (All versions < V17 Update 5), SIMATIC HMI KTP400 Basic (All versions < V17 Update 5), SIMATIC HMI KTP700 Basic (All versions < V17 Update 5), SIMATIC HMI KTP900 Basic (All versions < V17 Update 5), SIPLUS HMI KTP1200 BASIC (All versions < V17 Update 5), SIPLUS HMI KTP400 BASIC (All versions < V17 Update 5), SIPLUS HMI KTP700 BASIC (All versions < V17 Update 5), SIPLUS HMI KTP900 BASIC (All versions < V17 Update 5). Affected devices do not properly validate input sent to certain services over TCP. This could allow an unauthenticated remote attacker to cause a permanent denial of service condition (requiring a device reboot) by sending specially crafted TCP packets.