diff --git a/win32ss/gdi/gdi32/objects/bitmap.c b/win32ss/gdi/gdi32/objects/bitmap.c
index 91e8a0be9e..ed931f5300 100644
--- a/win32ss/gdi/gdi32/objects/bitmap.c
+++ b/win32ss/gdi/gdi32/objects/bitmap.c
@@ -214,6 +214,13 @@ CreateDIBSection(
 
     if (pConvertedInfo)
     {
+        if (BitmapInfo->bmiHeader.biSize != sizeof(BITMAPINFOHEADER))
+        {
+            DPRINT1("pConvertedInfo->bmiHeader.biSize != sizeof(BITMAPINFOHEADER).\n");
+            SetLastError(ERROR_INVALID_PARAMETER);
+            return NULL;
+        }
+
         // Verify header due to converted may == info.
         if (pConvertedInfo->bmiHeader.biSize >= sizeof(BITMAPINFOHEADER))
         {