diff --git a/core/lib/Drupal/Component/Utility/Xss.php b/core/lib/Drupal/Component/Utility/Xss.php
index a68ca2b..071ebd9 100644
--- a/core/lib/Drupal/Component/Utility/Xss.php
+++ b/core/lib/Drupal/Component/Utility/Xss.php
@@ -237,6 +237,7 @@ protected static function attributes($attributes) {
             $skip_protocol_filtering = substr($attribute_name, 0, 5) === 'data-' || in_array($attribute_name, array(
               'title',
               'alt',
+              'rel',
             ));
 
             $working = $mode = 1;