The Node Access User Reference module 5.x before 5.x-2.0-beta4 and 6.x before 6.x-2.0-beta6, a module for Drupal, interprets an empty CCK user reference as a reference to the anonymous user, which might allow remote attackers to bypass intended access restrictions to read or modify a node.

The Node access user reference module 6.x-3.x before 6.x-3.5 and 7.x-3.x before 7.x-3.10 for Drupal does not properly restrict access to content containing a user reference field when the author update/delete grants are enabled and the author's user account is deleted, which allows remote attackers to modify the content via unspecified vectors.