diff --git a/EdkNt32Pkg/Dxe/WinNtThunk/Bus/BlockIo/WinNtBlockIo.c b/EdkNt32Pkg/Dxe/WinNtThunk/Bus/BlockIo/WinNtBlockIo.c
index 2f65092747..014f8a6c06 100644
--- a/EdkNt32Pkg/Dxe/WinNtThunk/Bus/BlockIo/WinNtBlockIo.c
+++ b/EdkNt32Pkg/Dxe/WinNtThunk/Bus/BlockIo/WinNtBlockIo.c
@@ -204,14 +204,15 @@ Returns:
   if (DiskType == EfiWinNtVirtualDisks) {
     WinNtIo->WinNtThunk->SPrintf (
                           Buffer,
+                          sizeof (Buffer),
                           L"Diskfile%d",
                           WinNtIo->InstanceNumber
                           );
   } else {
     if (*Str >= 'A' && *Str <= 'Z' || *Str >= 'a' && *Str <= 'z') {
-      WinNtIo->WinNtThunk->SPrintf (Buffer, L"\\\\.\\%c:", *Str);
+      WinNtIo->WinNtThunk->SPrintf (Buffer, sizeof (Buffer), L"\\\\.\\%c:", *Str);
     } else {
-      WinNtIo->WinNtThunk->SPrintf (Buffer, L"\\\\.\\PHYSICALDRIVE%c", *Str);
+      WinNtIo->WinNtThunk->SPrintf (Buffer, sizeof (Buffer), L"\\\\.\\PHYSICALDRIVE%c", *Str);
     }
 
     Str++;
diff --git a/EdkNt32Pkg/Dxe/WinNtThunk/Bus/WinNtBusDriver/WinNtBusDriver.c b/EdkNt32Pkg/Dxe/WinNtThunk/Bus/WinNtBusDriver/WinNtBusDriver.c
index 73a345a431..d591151c14 100644
--- a/EdkNt32Pkg/Dxe/WinNtThunk/Bus/WinNtBusDriver/WinNtBusDriver.c
+++ b/EdkNt32Pkg/Dxe/WinNtThunk/Bus/WinNtBusDriver/WinNtBusDriver.c
@@ -462,7 +462,7 @@ Returns:
 
         WinNtDevice->ControllerNameTable = NULL;
 
-        WinNtThunk->SPrintf (ComponentName, L"%s", WinNtDevice->WinNtIo.EnvString);
+        WinNtThunk->SPrintf (ComponentName, sizeof (ComponentName), L"%s", WinNtDevice->WinNtIo.EnvString);
 
         WinNtDevice->DevicePath = WinNtBusCreateDevicePath (
                                     ParentDevicePath,