CVE-2017-17715
The saveFile method in MediaController.java in the Telegram Messenger application before 2017-12-08 for Android allows directory traversal via a pathname obtained in a file-transfer request from a remote peer, as demonstrated by writing to tgnet.dat or tgnet.dat.bak.
Date published : 2017-12-16
https://bugs.chromium.org/p/project-zero/issues/detail?id=1470