LINE client for iOS before 11.15.0 might expose authentication information for a certain service to external entities under certain conditions. This is usually impossible, but in combination with a server-side bug, attackers could get this information.
LINE for iOS version 7.1.3 to 7.1.5 does not verify X.509 certificates from SSL servers, which allows man-in-the-middle attackers to spoof servers and obtain sensitive information via a crafted certificate.