diff --git a/dlls/krnl386.exe16/vxd.c b/dlls/krnl386.exe16/vxd.c
index 5d280fb2fda..c0f16329027 100644
--- a/dlls/krnl386.exe16/vxd.c
+++ b/dlls/krnl386.exe16/vxd.c
@@ -140,25 +140,28 @@ HANDLE __wine_vxd_open( LPCWSTR filenameW, DWORD access, SECURITY_ATTRIBUTES *sa
     int i;
     HANDLE handle;
     HMODULE module;
-    WCHAR *p, name[16];
+    WCHAR *p, name[13];
 
     /* normalize the filename */
 
-    if (lstrlenW( filenameW ) >= ARRAY_SIZE(name) - 4 ||
-        wcschr( filenameW, '/' ) || wcschr( filenameW, '\\' ))
+    if (wcschr( filenameW, '/' ) || wcschr( filenameW, '\\' ))
     {
         SetLastError( ERROR_FILE_NOT_FOUND );
         return 0;
     }
-    lstrcpyW( name, filenameW );
-    wcslwr( name );
-    p = wcschr( name, '.' );
-    if (!p) lstrcatW( name, dotVxDW );
-    else if (wcsicmp( p, dotVxDW ))  /* existing extension has to be .vxd */
+    p = wcschr( filenameW, '.' );
+    if (!p && lstrlenW( filenameW ) <= 8) {
+        lstrcpyW( name, filenameW );
+        lstrcatW( name, dotVxDW );
+    }
+    else if (p && wcsicmp( p, dotVxDW ) == 0 && lstrlenW( filenameW ) <= 12)  /* existing extension has to be .vxd */
+        lstrcpyW( name, filenameW );
+    else
     {
         SetLastError( ERROR_FILE_NOT_FOUND );
         return 0;
     }
+    wcslwr( name );
 
     /* try to load the module first */