modules/openid/xrds.inc in Drupal 6.x before 6.33 and 7.x before 7.31 allows remote attackers to have unspecified impact via a crafted DOCTYPE declaration in an XRDS document.
http://cgit.drupalcode.org/drupal/diff/modules/openid/xrds.inc?id=1849830
http://openwall.com/lists/oss-security/2014/08/16/4