Index: src/wp-includes/rest-api.php
===================================================================
--- src/wp-includes/rest-api.php	(revision 38995)
+++ src/wp-includes/rest-api.php	(working copy)
@@ -513,7 +513,7 @@
 
 	if ( $origin ) {
 		header( 'Access-Control-Allow-Origin: ' . esc_url_raw( $origin ) );
-		header( 'Access-Control-Allow-Methods: POST, GET, OPTIONS, PUT, DELETE' );
+		header( 'Access-Control-Allow-Methods: OPTIONS, GET, POST, PUT, PATCH, DELETE' );
 		header( 'Access-Control-Allow-Credentials: true' );
 		header( 'Vary: Origin' );
 	}