IcedTea-Web before 1.5.3 and 1.6.x before 1.6.1 does not properly determine the origin of unsigned applets, which allows remote attackers to bypass the approval process or trick users into approving applet execution via a crafted web page.
https://bugzilla.redhat.com/show_bug.cgi?id=1233697
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