diff --git a/core/modules/system/system.module b/core/modules/system/system.module
old mode 100644
new mode 100755
index a1a6b71..7ad70b9
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -661,7 +661,8 @@ function system_page_attachments(array &$page) {
   // @see \Drupal\Core\Utility\LinkGenerator::generate()
   // @see template_preprocess_links()
   // @see \Drupal\Core\EventSubscriber\ActiveLinkResponseFilter
-  if (\Drupal::currentUser()->isAuthenticated()) {
+  $route_name = \Drupal::request()->attributes->get('_route');
+  if (\Drupal::currentUser()->isAuthenticated() || 'system.404' === $route_name) {
     $page['#attached']['library'][] = 'core/drupal.active-link';
   }
 }