diff --git a/wp-includes/rest-api.php b/wp-includes/rest-api.php
index 620ca925b9..6da931e77a 100644
--- a/wp-includes/rest-api.php
+++ b/wp-includes/rest-api.php
@@ -408,6 +408,7 @@ function rest_send_cors_headers( $value ) {
 		header( 'Access-Control-Allow-Origin: ' . esc_url_raw( $origin ) );
 		header( 'Access-Control-Allow-Methods: POST, GET, OPTIONS, PUT, DELETE' );
 		header( 'Access-Control-Allow-Credentials: true' );
+		header( 'Vary: Origin' );
 	}
 
 	return $value;
diff --git a/wp-includes/version.php b/wp-includes/version.php
index a7eeff968f..1c07ea222b 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.7-alpha-38805';
+$wp_version = '4.7-alpha-38806';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.