diff --git a/core/userrights.class.inc.php b/core/userrights.class.inc.php
index a53f1ac68..b3ece23b7 100644
--- a/core/userrights.class.inc.php
+++ b/core/userrights.class.inc.php
@@ -161,6 +161,7 @@ abstract class UserRightsAddOnAPI
 }
 
 
+require_once(APPROOT.'/application/cmdbabstract.class.inc.php');
 abstract class User extends cmdbAbstractObject
 {
 	public static function Init()