IcedTea-Web before 1.5.3 and 1.6.x before 1.6.1 does not properly sanitize applet URLs, which allows remote attackers to inject applets into the .appletTrustSettings configuration file and bypass user approval to execute the applet via a crafted web page, possibly related to line breaks.
https://bugzilla.redhat.com/show_bug.cgi?id=1233667
http://www.ubuntu.com/usn/USN-2817-1
http://www.securitytracker.com/id/1033780
http://www.oracle.com/technetwork/topics/security/linuxbulletinapr2016-2952096.html
http://rhn.redhat.com/errata/RHSA-2016-0778.html
http://mail.openjdk.java.net/pipermail/distro-pkg-dev/2015-September/033546.html
http://lists.opensuse.org/opensuse-security-announce/2015-09/msg00019.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-September/167130.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-September/167120.html