The session backends in Django before 1.4.21, 1.5.x through 1.6.x, 1.7.x before 1.7.9, and 1.8.x before 1.8.3 allows remote attackers to cause a denial of service (session store consumption) via multiple requests with unique session keys.
https://www.djangoproject.com/weblog/2015/jul/08/security-releases/
https://security.gentoo.org/glsa/201510-06
http://www.ubuntu.com/usn/USN-2671-1
http://www.securitytracker.com/id/1032820
http://www.securityfocus.com/bid/75666
http://www.oracle.com/technetwork/topics/security/bulletinoct2015-2511968.html
http://www.debian.org/security/2015/dsa-3305
http://rhn.redhat.com/errata/RHSA-2015-1686.html
http://rhn.redhat.com/errata/RHSA-2015-1678.html
http://lists.opensuse.org/opensuse-updates/2015-10/msg00046.html
http://lists.opensuse.org/opensuse-updates/2015-10/msg00043.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-November/172084.html