diff --git a/src/wp-includes/kses.php b/src/wp-includes/kses.php
index 69d897efc1..ba96b089e5 100644
--- a/src/wp-includes/kses.php
+++ b/src/wp-includes/kses.php
@@ -441,6 +441,7 @@ if ( ! CUSTOM_TAGS ) {
 		'q' => array(
 			'cite' => true,
 		),
+		's' => array(),
 		'strike' => array(),
 		'strong' => array(),
 	);