The LiveConnect implementation in plugin/icedteanp/IcedTeaNPPlugin.cc in IcedTea-Web before 1.4.2 allows local users to read the messages between a Java applet and a web browser by pre-creating a temporary socket file with a predictable name in /tmp.
https://bugzilla.redhat.com/show_bug.cgi?id=1010958
http://www.ubuntu.com/usn/USN-2131-1
http://secunia.com/advisories/57036
http://seclists.org/oss-sec/2014/q1/282
http://mail.openjdk.java.net/pipermail/distro-pkg-dev/2014-February/026192.html
http://lists.opensuse.org/opensuse-updates/2014-02/msg00089.html