A vulnerability has been identified in SIMATIC PCS 7 V9.1 (All versions < V9.1 SP2 UC04), SIMATIC WinCC Runtime Professional V17 (All versions < V17 Update 8), SIMATIC WinCC Runtime Professional V18 (All versions < V18 Update 4), SIMATIC WinCC Runtime Professional V19 (All versions < V19 Update 1), SIMATIC WinCC V7.5 (All versions < V7.5 SP2 Update 16), SIMATIC WinCC V8.0 (All versions < V8.0 Update 5). The affected products do not properly validate the input provided in the login dialog box. An attacker could leverage this vulnerability to cause a persistent denial of service condition.