[rntksi]

Telegram actually handles this well (better than some other similar chat apps like LINE, Viber, ...)

It has an option inside Security and Privacy, in the subsection on "Calls", where you can limit who can contact you using P2P calls and who will have the call routed through a central server of Telegram.

So usually you can restrict P2P only to your contacts for example, and everyone else will have calls routed to Telegram central server (or just disable calling altogether for everyone else)

[judge2020]

What is the default?

[rntksi]

This issue has been known since 2018 https://www.bleepingcomputer.com/news/security/telegram-leak...

The default is calls are P2P enabled