diff --git a/app/controllers/course/forum/forum_controller.php b/app/controllers/course/forum/forum_controller.php
index 1812be94e7d64370f7b7bb84723129313a9b7224..d826b25f62f0c252fe010951ec21086ae9b43012 100644
--- a/app/controllers/course/forum/forum_controller.php
+++ b/app/controllers/course/forum/forum_controller.php
@@ -1,6 +1,6 @@
 <?php
 
-class ForumController extends StudipController {
+abstract class ForumController extends StudipController {
     protected $with_session = true;
 
     /* * * * * * * * * * * * * * * * * * * * * * * * * */
diff --git a/app/controllers/module/mvv_controller.php b/app/controllers/module/mvv_controller.php
index 303f44a53779f469108bebe2653a3b4ea3dcf771..f54d8cf0645ce67f1afcee59a3884e94dbb8e978 100644
--- a/app/controllers/module/mvv_controller.php
+++ b/app/controllers/module/mvv_controller.php
@@ -5,7 +5,7 @@
  * @since       3.5
  */
 
-class MVVController extends AuthenticatedController
+abstract class MVVController extends AuthenticatedController
 {
     /**
      * The maximum number of items listed on a page.
diff --git a/app/controllers/settings/settings.php b/app/controllers/settings/settings.php
index 2f4534c30905681ac15e3bbc4d1cc3264957484a..6609f9192f72af83f2c4fc13e3feb82c458c5a28 100644
--- a/app/controllers/settings/settings.php
+++ b/app/controllers/settings/settings.php
@@ -15,7 +15,7 @@
 
 require_once 'lib/messaging.inc.php';
 
-class Settings_SettingsController extends AuthenticatedController
+abstract class Settings_SettingsController extends AuthenticatedController
 {
     // Stores message which shall be send to the user via email
     protected $private_messages = [];