diff --git a/wp-includes/pluggable.php b/wp-includes/pluggable.php
index 1e6b220f01..dc10c7f393 100644
--- a/wp-includes/pluggable.php
+++ b/wp-includes/pluggable.php
@@ -1080,6 +1080,10 @@ if ( !function_exists('check_ajax_referer') ) :
  *                   0-12 hours ago, 2 if the nonce is valid and generated between 12-24 hours ago.
  */
 function check_ajax_referer( $action = -1, $query_arg = false, $die = true ) {
+	if ( -1 == $action ) {
+		_doing_it_wrong( __FUNCTION__, __( 'You should specify a nonce action to be verified by using the first parameter.' ), '4.7' );
+	}
+
 	$nonce = '';
 
 	if ( $query_arg && isset( $_REQUEST[ $query_arg ] ) )
diff --git a/wp-includes/version.php b/wp-includes/version.php
index e3cc6b8dc9..009ab2d9a7 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.7-alpha-38419';
+$wp_version = '4.7-alpha-38420';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.