    public function validate($string, $config, $context) {

        static $colors = null;
        if ($colors === null) $colors = $config->get('Core.ColorKeywords');

        $string = trim($string);

        if (empty($string)) return false;
        $lower = strtolower($string);
        if (isset($colors[$lower])) return $colors[$lower];
        if ($string[0] === '#') $hex = substr($string, 1);
        else $hex = $string;

        $length = strlen($hex);
        if ($length !== 3 && $length !== 6) return false;
        if (!ctype_xdigit($hex)) return false;
        if ($length === 3) $hex = $hex[0].$hex[0].$hex[1].$hex[1].$hex[2].$hex[2];

        return "#$hex";

    }
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.