ModelMultipleChoiceField in Django 1.6.x before 1.6.10 and 1.7.x before 1.7.3, when show_hidden_initial is set to True, allows remote attackers to cause a denial of service by submitting duplicate values, which triggers a large number of SQL queries.
https://www.djangoproject.com/weblog/2015/jan/13/security/
http://www.mandriva.com/security/advisories?name=MDVSA-2015:109
http://ubuntu.com/usn/usn-2469-1
http://secunia.com/advisories/62309
http://secunia.com/advisories/62285
http://lists.opensuse.org/opensuse-updates/2015-09/msg00035.html
http://lists.opensuse.org/opensuse-updates/2015-04/msg00001.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-January/148696.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-January/148608.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-January/148485.html