            $uri->path = implode('/', $new_stack);
        } else {
            // absolute path, but still we should collapse
            $uri->path = implode('/', $this->_collapseStack(explode('/', $uri->path)));
        }
        // re-combine
        $uri->scheme = $this->base->scheme;
        if (is_null($uri->userinfo)) $uri->userinfo = $this->base->userinfo;
        if (is_null($uri->host))     $uri->host     = $this->base->host;
        if (is_null($uri->port))     $uri->port     = $this->base->port;
        return true;
    }
The software does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.