Algorithmic complexity vulnerability in the _filter_url function in the text filtering system (modules/filter/filter.module) in Drupal 7.x before 7.14 allows remote authenticated users with certain roles to cause a denial of service (CPU consumption) via a long email address.
http://www.securityfocus.com/bid/53368
http://www.mandriva.com/security/advisories?name=MDVSA-2013:074
http://secunia.com/advisories/49012
http://drupalcode.org/project/drupal.git/commit/db79496ae983447506f016a20738c3d7e5d059fa
http://drupal.org/node/1558468