Index: /trunk/src/VBox/Storage/VDI.cpp
===================================================================
--- /trunk/src/VBox/Storage/VDI.cpp	(revision 66504)
+++ /trunk/src/VBox/Storage/VDI.cpp	(revision 66505)
@@ -1381,5 +1381,5 @@
     AssertReturn((VALID_PTR(pszFilename) && *pszFilename), VERR_INVALID_PARAMETER);
 
-    PVDIIMAGEDESC pImage = (PVDIIMAGEDESC)RTMemAllocZ(sizeof(VDIIMAGEDESC));
+    PVDIIMAGEDESC pImage = (PVDIIMAGEDESC)RTMemAllocZ(RT_UOFFSETOF(VDIIMAGEDESC, RegionList.aRegions[1]));
     if (RT_LIKELY(pImage))
     {
Index: /trunk/src/VBox/Storage/VMDK.cpp
===================================================================
--- /trunk/src/VBox/Storage/VMDK.cpp	(revision 66504)
+++ /trunk/src/VBox/Storage/VMDK.cpp	(revision 66505)
@@ -5186,5 +5186,5 @@
 
     int rc = VINF_SUCCESS;
-    PVMDKIMAGE pImage = (PVMDKIMAGE)RTMemAllocZ(sizeof(VMDKIMAGE));
+    PVMDKIMAGE pImage = (PVMDKIMAGE)RTMemAllocZ(RT_UOFFSETOF(VMDKIMAGE, RegionList.aRegions[1]));
     if (RT_LIKELY(pImage))
     {