It could happen anytime coz we didn't even know whether there's a security branch on huobi that's not yet discovered.
BTW any exchange can be hacked anytime as long as there's a vulnerable feature or just like the kucoin's case when it was getting hacked by phishing email.

Anything can happen in crypto. I hope that huobi will never be hacked. This is why security is the most important part in centralized exchange site.