diff --git a/wp-includes/kses.php b/wp-includes/kses.php
index 6a579b8d91..2c0e075ff4 100644
--- a/wp-includes/kses.php
+++ b/wp-includes/kses.php
@@ -230,6 +230,7 @@ if ( ! CUSTOM_TAGS ) {
 			'border'   => true,
 			'height'   => true,
 			'hspace'   => true,
+			'loading'  => true,
 			'longdesc' => true,
 			'vspace'   => true,
 			'src'      => true,
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 309eddee7b..8cf43c9d78 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.5-beta3-48571';
+$wp_version = '5.5-beta3-48572';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.