    public function prepare($config) {
        $def = $config->getDefinition('URI');
        $this->base = $def->base;
        if (is_null($this->base)) {
            trigger_error('URI.MakeAbsolute is being ignored due to lack of value for URI.Base configuration', E_USER_WARNING);
            return false;
        }
        $this->base->fragment = null; // fragment is invalid for base URI
        $stack = explode('/', $this->base->path);
        array_pop($stack); // discard last segment
        $stack = $this->_collapseStack($stack); // do pre-parsing
        $this->basePathStack = $stack;
        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.