The Certify module before 6.x-2.3 for Drupal does not properly perform node access checks, which allows remote authenticated users to bypass intended access restrictions and obtain sensitive PDF certificate information via vectors related to "showing (and creating) the PDF certificates."
https://www.drupal.org/node/2415947
https://www.drupal.org/node/2407081
http://www.securityfocus.com/bid/74282