diff --git a/wp-includes/rest-api/endpoints/class-wp-rest-users-controller.php b/wp-includes/rest-api/endpoints/class-wp-rest-users-controller.php
index d366c70371..45769808db 100644
--- a/wp-includes/rest-api/endpoints/class-wp-rest-users-controller.php
+++ b/wp-includes/rest-api/endpoints/class-wp-rest-users-controller.php
@@ -1010,6 +1010,9 @@ class WP_REST_Users_Controller extends WP_REST_Controller {
 						'type'    => 'string',
 					),
 					'context'     => array( 'edit' ),
+					'arg_options' => array(
+						'sanitize_callback' => 'wp_parse_slug_list',
+					),
 				),
 				'password'        => array(
 					'description' => __( 'Password for the resource (never included).' ),
diff --git a/wp-includes/version.php b/wp-includes/version.php
index cd8bb46c4b..ce11867f83 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.7-beta1-39055';
+$wp_version = '4.7-beta1-39056';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.