Algorithmic complexity vulnerability in the forms library in Django 1.0 before 1.0.4 and 1.1 before 1.1.1 allows remote attackers to cause a denial of service (CPU consumption) via a crafted (1) EmailField (email address) or (2) URLField (URL) that triggers a large amount of backtracking in a regular expression.
https://exchange.xforce.ibmcloud.com/vulnerabilities/53727
http://www.vupen.com/english/advisories/2009/2871
http://www.securityfocus.com/bid/36655
http://www.openwall.com/lists/oss-security/2009/10/13/6
http://www.djangoproject.com/weblog/2009/oct/09/security/
http://www.debian.org/security/2009/dsa-1905
http://secunia.com/advisories/36968
http://secunia.com/advisories/36948
http://groups.google.com/group/django-users/browse_thread/thread/15df9e45118dfc51/