diff --git a/core/includes/form.inc b/core/includes/form.inc
index 80afe45..0109857 100644
--- a/core/includes/form.inc
+++ b/core/includes/form.inc
@@ -4023,6 +4023,11 @@ function form_process_vertical_tabs($element, &$form_state) {
     '#parents' => $element['#parents'],
   );
 
+  // Details within a vertical tab do not require a title.
+  $details_validation = element_info_property('details', '#property_validate');
+  unset($details_validation['#title']);
+  $element['group']['#property_validate'] = $details_validation;
+
   // Add an invisible label for accessibility.
   if (!isset($element['#title'])) {
     $element['#title'] = t('Vertical Tabs');