CVE-2020-12474

Telegram Desktop through 2.0.1, Telegram through 6.0.1 for Android, and Telegram through 6.0.1 for iOS allow an IDN Homograph attack via Punycode in a public URL or a group chat invitation URL.

CVE-2018-17780

Telegram Desktop (aka tdesktop) 1.3.14, and Telegram 3.3.0.0 WP8.1 on Windows, leaks end-user public and private IP addresses during a call because of an unsafe default behavior in which P2P connections are accepted from clients outside of the My Contacts list.