diff --git a/core/core.services.yml b/core/core.services.yml
index a7a2b3b..90503b1 100644
--- a/core/core.services.yml
+++ b/core/core.services.yml
@@ -471,6 +471,7 @@ services:
   app.root.factory:
     class: Drupal\Core\AppRootFactory
     arguments: ['@kernel']
+    private: true
   controller_resolver:
     class: Drupal\Core\Controller\ControllerResolver
     arguments: ['@class_resolver']