The default configuration of IBUS 1.5.4, and possibly 1.5.2 and earlier, when IBus.InputPurpose.PASSWORD is not set and used with GNOME 3, does not obscure the entered password characters, which allows physically proximate attackers to obtain a user password by reading the lockscreen.

A flaw was discovered in ibus in versions before 1.5.22 that allows any unprivileged user to monitor and send method calls to the ibus bus of another user due to a misconfiguration in the DBus server setup. A local attacker may use this flaw to intercept all keystrokes of a victim user who is using the graphical interface, change the input method engine, or modify other input related configurations of the victim user.