diff --git "a/win32ss/user/user32/misc/exticon.c" "b/win32ss/user/user32/misc/exticon.c"
index 09074c5c6a4..2c5f20c9932 100644
--- "a/win32ss/user/user32/misc/exticon.c"
+++ "b/win32ss/user/user32/misc/exticon.c"
@@ -616,6 +616,8 @@ static UINT ICO_ExtractIconExW(
             goto end;
         }
 
+      if ((ULONG_PTR)(rootresdir + 1) > (ULONG_PTR)peimage + fsizel) goto end;
+
 	  /* search for the group icon directory */
 	  if (!(icongroupresdir = find_entry_by_id(rootresdir, LOWORD(RT_GROUP_ICON), rootresdir)))
 	  {