French Government launched Tchap last week, touting it as more secure than WhatsApp and Telegram. A security researcher discovered an email validation error when it comes to creating an account. He modified the token field to trick the validation mechanism by supplying a specially formatted email address. The open-source administrator behind the source code for the app, Matrix, explained the vulnerability in more detail late last week. Matrix updated the code on the backend the same day that Baptiste notified it of the vulnerability, so that it now requires that the parsed email address is the same as the input address.
Source: https://threatpost.com/frances-secure-telegram-messaging-hacked/144010/