@Sp3000 It's sandboxed (no write access, no internet), I've blocked outgoing SMTP connections with iptables (additional security measure) and set a conservative process limit (to prevent fork bombs). I hope that's enough.
@Sp3000 Me too. :P In the end, I think sandboxing interpreters will be more secure than my current approach though, which consists in trusting the authors of a gazillion esolang interpreters.