We have recently experienced a security incident that may potentially involve your Plex account information. We believe the actual impact of this incident is limited; however, action is required from you to ensure your account remains secure. What happened An unauthorized third party accessed a limited subset of customer data from one of our databases. While we quickly contained the incident, information that was accessed included emails, usernames, securely hashed passwords and authentication ...
Not really true for self hosting a media library though, as this all relies on indexers, torrent sites, Usenet providers, metadata providers, subtitle providers, etc. If you host it for others outside of your household, you also rely on your ISP, their ISP, etc.