diff --git a/core/modules/ckeditor/ckeditor.admin.inc b/core/modules/ckeditor/ckeditor.admin.inc
index 4ee12bb..3a9a9c3 100644
--- a/core/modules/ckeditor/ckeditor.admin.inc
+++ b/core/modules/ckeditor/ckeditor.admin.inc
@@ -66,10 +66,10 @@ function template_preprocess_ckeditor_settings_toolbar(&$variables) {
   $build_button_item = function($button, $rtl) {
     // Value of the button item.
     if (isset($button['image_alternative' . $rtl])) {
-      $value = SafeMarkup::set($button['image_alternative' . $rtl]);
+      $value = $button['image_alternative' . $rtl];
     }
     elseif (isset($button['image_alternative'])) {
-      $value = SafeMarkup::set($button['image_alternative']);
+      $value = $button['image_alternative'];
     }
     elseif (isset($button['image'])) {
       $value = array(
diff --git a/core/modules/ckeditor/src/Plugin/CKEditorPlugin/Internal.php b/core/modules/ckeditor/src/Plugin/CKEditorPlugin/Internal.php
index c405c7f..c57af49 100644
--- a/core/modules/ckeditor/src/Plugin/CKEditorPlugin/Internal.php
+++ b/core/modules/ckeditor/src/Plugin/CKEditorPlugin/Internal.php
@@ -9,6 +9,7 @@
 
 use Drupal\ckeditor\CKEditorPluginBase;
 use Drupal\Component\Utility\NestedArray;
+use Drupal\Component\Utility\SafeMarkup;
 use Drupal\Core\Cache\Cache;
 use Drupal\Core\Cache\CacheBackendInterface;
 use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
@@ -127,7 +128,8 @@ public function getConfig(Editor $editor) {
    */
   public function getButtons() {
     $button = function($name, $direction = 'ltr') {
-      return '<a href="#" class="cke-icon-only cke_' . $direction . '" role="button" title="' . $name . '" aria-label="' . $name . '"><span class="cke_button_icon cke_button__' . str_replace(' ', '', $name) . '_icon">' . $name . '</span></a>';
+      $clean_name = str_replace(' ', '', $name);
+      return SafeMarkup::format('<a href="#" class="cke-icon-only cke_@direction" role="button" title="@name" aria-label="@name"><span class="cke_button_icon cke_button__@cleanname_icon">@name</span></a>', ['@direction' => $direction, '@name' => $name, '@cleanname' => $clean_name]);
     };
 
     return array(