The utils.html.strip_tags function in Django 1.6.x before 1.6.11, 1.7.x before 1.7.7, and 1.8.x before 1.8c1, when using certain versions of Python, allows remote attackers to cause a denial of service (infinite loop) by increasing the length of the input string.
https://www.djangoproject.com/weblog/2015/mar/18/security-releases/
http://www.ubuntu.com/usn/USN-2539-1
http://www.securityfocus.com/bid/73322
http://www.oracle.com/technetwork/topics/security/bulletinapr2015-2511959.html
http://lists.opensuse.org/opensuse-updates/2015-04/msg00001.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-April/155421.html