diff --git a/MdeModulePkg/Core/Dxe/Gcd/gcd.c b/MdeModulePkg/Core/Dxe/Gcd/gcd.c
index 1d023548d3..3cadab29dc 100644
--- a/MdeModulePkg/Core/Dxe/Gcd/gcd.c
+++ b/MdeModulePkg/Core/Dxe/Gcd/gcd.c
@@ -2473,6 +2473,9 @@ Returns:
       if (MemorySpaceMap[Index].ImageHandle == NULL) {
         BaseAddress  = PageAlignAddress (MemorySpaceMap[Index].BaseAddress);
         Length       = PageAlignLength  (MemorySpaceMap[Index].BaseAddress + MemorySpaceMap[Index].Length - BaseAddress);
+        if (Length == 0 || MemorySpaceMap[Index].BaseAddress + MemorySpaceMap[Index].Length < BaseAddress) {
+          continue;
+        }
         CoreAddMemoryDescriptor (
           EfiConventionalMemory,
           BaseAddress,
diff --git a/MdeModulePkg/Core/Dxe/Mem/Page.c b/MdeModulePkg/Core/Dxe/Mem/Page.c
index 0ac2aa5c91..97179dec85 100644
--- a/MdeModulePkg/Core/Dxe/Mem/Page.c
+++ b/MdeModulePkg/Core/Dxe/Mem/Page.c
@@ -1432,7 +1432,7 @@ Returns:
   //
   // Build the map
   //
-  ZeroMem (MemoryMap, Size);
+  ZeroMem (MemoryMap, BufferSize);
   for (Link = gMemoryMap.ForwardLink; Link != &gMemoryMap; Link = Link->ForwardLink) {
     Entry = CR (Link, MEMORY_MAP, Link, MEMORY_MAP_SIGNATURE);
     ASSERT (Entry->VirtualStart == 0);