diff --git a/src/Core/CoreServiceProvider.php b/src/Core/CoreServiceProvider.php
index 478baf97d..68ec477e0 100644
--- a/src/Core/CoreServiceProvider.php
+++ b/src/Core/CoreServiceProvider.php
@@ -105,6 +105,7 @@ class CoreServiceProvider extends AbstractServiceProvider
 
         $events->subscribe('Flarum\Core\Listener\DiscussionMetadataUpdater');
         $events->subscribe('Flarum\Core\Listener\UserMetadataUpdater');
+        $events->subscribe('Flarum\Core\Listener\ExtensionValidator');
         $events->subscribe('Flarum\Core\Listener\EmailConfirmationMailer');
         $events->subscribe('Flarum\Core\Listener\DiscussionRenamedNotifier');