diff --git a/core/modules/system/src/Form/DateFormatEditForm.php b/core/modules/system/src/Form/DateFormatEditForm.php
index cec0020..fd96054 100644
--- a/core/modules/system/src/Form/DateFormatEditForm.php
+++ b/core/modules/system/src/Form/DateFormatEditForm.php
@@ -3,6 +3,7 @@
 namespace Drupal\system\Form;
 
 use Drupal\Core\Form\FormStateInterface;
+use Drupal\Component\Utility\Xss;
 
 /**
  * Provides a form for editing a date format.
@@ -16,7 +17,7 @@ public function form(array $form, FormStateInterface $form_state) {
     $form = parent::form($form, $form_state);
 
     $now = t('Displayed as %date', array('%date' => $this->dateFormatter->format(REQUEST_TIME, $this->entity->id())));
-    $form['date_format_pattern']['#field_suffix'] = ' <small data-drupal-date-formatter="preview">' . $now . '</small>';
+    $form['date_format_pattern']['#field_suffix'] = ' <small data-drupal-date-formatter="preview">' . Xss::filter($now, array('script')) . '</small>';
     $form['date_format_pattern']['#default_value'] = $this->entity->getPattern();
 
     return $form;