diff --git a/components/Search/Search.php b/components/Search/Search.php
index e595387b0f..fe14441fd1 100644
--- a/components/Search/Search.php
+++ b/components/Search/Search.php
@@ -25,6 +25,7 @@ namespace Component\Search;
 
 use App\Core\Event;
 use App\Core\Form;
+use App\Util\Exception\ClientException;
 use function App\Core\I18n\_m;
 use App\Core\Modules\Component;
 use App\Util\Common;
@@ -109,8 +110,11 @@ class Search extends Component
                     /** @var SubmitButton $subscribe */
                     $subscribe = $form->get('subscribe_to_search');
                     if ($subscribe->isClicked()) {
-                        // TODO ensure title is set
-                        Event::handle('AppendFeed', [$actor, $data['title'], 'search', ['q' => $data['search_query']]]);
+                        if (!\is_null($data['title'])) {
+                            Event::handle('AppendFeed', [$actor, $data['title'], 'search', ['q' => $data['search_query']]]);
+                        } else {
+                            throw new ClientException(_m('Empty title is not allowed.'));
+                        }
                         $redirect = true;
                     }
                 }