            $this->contentSets->generateChildDef($def, $module);
        }

        // This can occur if there is a blank definition, but no base to
        // mix it in with
        if (!$def) return false;

        // add information on required attributes
        foreach ($def->attr as $attr_name => $attr_def) {
            if ($attr_def->required) {
                $def->required_attr[] = $attr_name;
            }
        }

        return $def;

    }
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.