Index: src/wp-includes/class-wp-xmlrpc-server.php
===================================================================
--- src/wp-includes/class-wp-xmlrpc-server.php	(revision 46146)
+++ src/wp-includes/class-wp-xmlrpc-server.php	(working copy)
@@ -732,7 +732,7 @@
 	 * @return bool if `$args` contains at least $count arguments.
 	 */
 	protected function minimum_args( $args, $count ) {
-		if ( count( $args ) < $count ) {
+		if ( count( (array)$args ) < $count ) {
 			$this->error = new IXR_Error( 400, __( 'Insufficient arguments passed to this XML-RPC method.' ) );
 			return false;
 		}