diff --git a/core/includes/form.inc b/core/includes/form.inc
index 952cbd4..05f640a 100644
--- a/core/includes/form.inc
+++ b/core/includes/form.inc
@@ -192,7 +192,7 @@ function template_preprocess_fieldset(&$variables) {
   $element = $variables['element'];
   Element::setAttributes($element, array('id'));
   Element\RenderElement::setAttributes($element);
-  $variables['attributes'] = $element['#attributes'];
+  $variables['attributes'] = isset($element['#attributes']) ? $element['#attributes'] : array();
   $variables['prefix'] = isset($element['#field_prefix']) ? $element['#field_prefix'] : NULL;
   $variables['suffix'] = isset($element['#field_suffix']) ? $element['#field_suffix'] : NULL;
   $variables['title_display'] = isset($element['#title_display']) ? $element['#title_display'] : NULL;