Denis Simonov, a security researcher, who is also known as n0a, recently highlighted the issue and wrote a simple tool to exploit it. TechCrunch verified the researcher’s findings by adding Simonov to the contacts of a newly created Telegram account. Simonov then called the account, and shortly after provided TechCrunch with the IP address of the computer where the experiment was being carried out.
Telegram boasts 700 million users all over the world, and has always marketed itself as a “secure” and “private” messaging app, even though experts have repeatedly warned that Telegram is not as secure as end-to-end encrypted app Signal, for example.
The fact that Telegram leaks your IP address to people in your contacts during a voice call has been known for years, but it’s likely that new, less technical users may not be aware."
