diff --git a/src/wp-includes/kses.php b/src/wp-includes/kses.php
index 531e6efea0..2e2f94a66d 100644
--- a/src/wp-includes/kses.php
+++ b/src/wp-includes/kses.php
@@ -119,6 +119,7 @@ if ( ! CUSTOM_TAGS ) {
 			'datetime' => true,
 		),
 		'dd' => array(),
+		'dfn' => array(),
 		'details' => array(
 			'align' => true,
 			'dir' => true,
@@ -235,6 +236,7 @@ if ( ! CUSTOM_TAGS ) {
 		'map' => array(
 			'name' => true,
 		),
+		'mark' => array(),
 		'menu' => array(
 			'type' => true,
 		),
@@ -257,6 +259,7 @@ if ( ! CUSTOM_TAGS ) {
 			'cite' => true,
 		),
 		's' => array(),
+		'samp' => array(),
 		'span' => array(
 			'dir' => true,
 			'align' => true,