    public function transform($attr, $config, $context) {
        if (!isset($attr[$this->name])) return $attr;
        $length = $this->confiscateAttr($attr, $this->name);
        if(ctype_digit($length)) $length .= 'px';
        $this->prependCSS($attr, $this->cssName . ":$length;");
        return $attr;
    }
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.