tl;dr: if a geolocation is sent via telegram "secret chat" (end-to-end encrypted), the telegram android app will use clear-text google maps api to display the m

tl;dr: if a geolocation is sent via telegram "secret chat" (end-to-end encrypted), the telegram android app will use clear-text google maps api to display the map, thus revealing the location to passive adversaries. according to a comment, this issue is already fixed in the source and an update for Google Play is in the works.