Drupal 6.x before 6.23 and 7.x before 7.11 does not verify that Attribute Exchange (AX) information is signed, which allows remote attackers to modify potentially sensitive AX information without detection via a man-in-the-middle (MITM) attack.
- http://openid.net/2011/05/05/attribute-exchange-security-alert/
No PoCs found on GitHub currently.