diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.c b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.c
index 982eea0f14..442fe1dad7 100644
--- a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.c
+++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.c
@@ -156,9 +156,9 @@ RuntimeServiceGetVariable (
   
   //
   // Init the communicate buffer. The buffer data size is:
-  // SMM_COMMUNICATE_HEADER_SIZE + SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + PayloadSize.
+  // SMM_COMMUNICATE_HEADER_SIZE + SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + PayloadSize + DataSize.
   //
-  PayloadSize = OFFSET_OF (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name) + StrSize (VariableName);
+  PayloadSize = OFFSET_OF (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name) + StrSize (VariableName) + *DataSize;
   Status = InitCommunicateBuffer ((VOID **)&SmmVariableHeader, PayloadSize, SMM_VARIABLE_FUNCTION_GET_VARIABLE);
   if (EFI_ERROR (Status)) {
     return Status;
diff --git a/SecurityPkg/VariableAuthenticated/RuntimeDxe/VariableSmmRuntimeDxe.c b/SecurityPkg/VariableAuthenticated/RuntimeDxe/VariableSmmRuntimeDxe.c
index 8aa568111f..2ef44e3a11 100644
--- a/SecurityPkg/VariableAuthenticated/RuntimeDxe/VariableSmmRuntimeDxe.c
+++ b/SecurityPkg/VariableAuthenticated/RuntimeDxe/VariableSmmRuntimeDxe.c
@@ -172,9 +172,9 @@ RuntimeServiceGetVariable (
   
   //
   // Init the communicate buffer. The buffer data size is:
-  // SMM_COMMUNICATE_HEADER_SIZE + SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + PayloadSize.
+  // SMM_COMMUNICATE_HEADER_SIZE + SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + PayloadSize + DataSize.
   //
-  PayloadSize = OFFSET_OF (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name) + StrSize (VariableName);
+  PayloadSize = OFFSET_OF (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name) + StrSize (VariableName) + *DataSize;
   Status = InitCommunicateBuffer ((VOID **)&SmmVariableHeader, PayloadSize, SMM_VARIABLE_FUNCTION_GET_VARIABLE);
   if (EFI_ERROR (Status)) {
     return Status;