The flaws stemmed from the way secret chat functionality operates and in the app’s handling of animated stickers. The flaws were discovered by Italy-based Shielder in iOS, Android, and macOS versions of the app. It’s worth noting that this is the second flaw uncovered in Telegram’s secret chat feature, following last week’s reports of a privacy-defeating bug in its macOS app that made it possible to access self-destructing audio and video messages long after they disappeared from secret chats. In March 2017, researchers from Check Point Research revealed a new form of attack against web versions of Telegram and WhatsApp.
Source: https://thehackernews.com/2021/02/a-sticker-sent-on-telegram-could-have.html