Ticket #21495: 21495.patch

wp-includes/user.php

@@ -1255 +1255 @@
                 $old_user_data = WP_User::get_data_by( 'id', $ID );
         } else {
                 $update = false;
+                // check for a password
+                if ( !isset($user_pass) || empty($user_pass) ){
+                        return new WP_Error('empty_user_password', __('Cannot create a user with an empty password.') );
+                }
                 // Hash the password
                 $user_pass = wp_hash_password($user_pass);
         }