diff --git a/EmulatorPkg/EmuGopDxe/GopInput.c b/EmulatorPkg/EmuGopDxe/GopInput.c
index 1d40b1d7d6..97a5fbc1ad 100644
--- a/EmulatorPkg/EmuGopDxe/GopInput.c
+++ b/EmulatorPkg/EmuGopDxe/GopInput.c
@@ -1,6 +1,6 @@
 /*++ @file
 
-Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
 Portions copyright (c) 2010 0 2011,Apple Inc. All rights reserved.<BR>
 This program and the accompanying materials
 are licensed and made available under the terms and conditions of the BSD License
@@ -442,11 +442,20 @@ EmuGopSimpleTextInExSetState (
   EFI_STATUS        Status;
   EFI_TPL           OldTpl;
 
+  if (KeyToggleState == NULL) {
+    return EFI_INVALID_PARAMETER;
+  }
+
   Private = GOP_PRIVATE_DATA_FROM_TEXT_IN_EX_THIS (This);
   if (Private->EmuGraphicsWindow == NULL) {
     return EFI_NOT_READY;
   }
 
+  if (((Private->KeyState.KeyToggleState & EFI_TOGGLE_STATE_VALID) != EFI_TOGGLE_STATE_VALID) ||
+      ((*KeyToggleState & EFI_TOGGLE_STATE_VALID) != EFI_TOGGLE_STATE_VALID)) {
+    return EFI_UNSUPPORTED;
+  }
+
   //
   // Enter critical section
   //