Django data leakage via querystring manipulation in admin

The administrative interface (contrib.admin) in Django before 1.4.14, 1.5.x before 1.5.9, 1.6.x before 1.6.6, and 1.7 before release candidate 3 does not check if a field represents a relationship between models, which allows remote authenticated users to obtain sensitive information via a to_field parameter in a popup action to an admin change form page, as demonstrated by a /admin/auth/user/?pop=1&t=password URI.