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.
https://groups.google.com/forum/#%21topic/ibus-user/mvCHDO1BJUw
https://github.com/ibus/ibus-anthy/commit/6aae0a9f145f536515e268dd6b25aa740a5edfe7
https://bugzilla.redhat.com/show_bug.cgi?id=1027028
http://lists.opensuse.org/opensuse-updates/2014-01/msg00045.html
http://lists.opensuse.org/opensuse-updates/2013-12/msg00024.html
http://lists.opensuse.org/opensuse-updates/2013-11/msg00036.html