http://protonmailrmez3lotccipshtkleegetolb73fuirgj7r4o4vfu7ozyd.onion/blog/email-security-ropemaker-vulnerability
As part of our email security efforts, our internal security team monitors numerous security mailing lists, forums, and other locations with relevant online chatter in order to identify and block threats before they can be exploited. In addition to our extensive internal efforts to protect Proton Mail users, we also host a bug bounty program to work with security researchers around the world in improving the security state of both Proton Mail and Proton VPN.