subject
There’s a famous hacker guy who setup a free VPN and he used it to monitor the people who were using the VPN, including some scammers that were using it.
So, worst thing that can happen if someone gets to see everything you do online.
You give a list of all the servers you connect to to the owner of the VPN rather than your isp
Being use in malicious botnet.
You’re an open book for whomever is operating that VPN. If you’re using a service that’s free, you’re the product. Just go with a privacy oriented VPN, they’re worth the money.
they can see all the sites you visit using dns and sni.