diff -u b/core/lib/Drupal/Core/Utility/LinkGenerator.php b/core/lib/Drupal/Core/Utility/LinkGenerator.php
--- b/core/lib/Drupal/Core/Utility/LinkGenerator.php
+++ b/core/lib/Drupal/Core/Utility/LinkGenerator.php
@@ -166,6 +166,7 @@
     }
     elseif ($url->isRouted() && $url->getRouteName() === '<button>') {
       $generated_link = new GeneratedButton();
+      $attributes['type'] = 'button';
       unset($attributes['href']);
     }
     else {