The request_path function in includes/bootstrap.inc in Drupal 7.14 and earlier allows remote attackers to obtain sensitive information via the q[] parameter to index.php, which reveals the installation path in an error message.

Cross-site request forgery (CSRF) vulnerability in Drupal 7.12 and earlier allows remote attackers to hijack the authentication of arbitrary users for requests that end a session via the user/logout URI. NOTE: the vendor disputes the significance of this issue, by considering the "security benefit against platform complexity and performance impact" and concluding that a change to the logout behavior is not planned because "for most sites it is not worth the trade-off.

The comment module in Drupal 5.x before 5.23 and 6.x before 6.18 allows remote authenticated users with certain privileges to bypass intended access restrictions and reinstate removed comments via a crafted URL, related to an "unpublishing bypass" issue.

The upload module in Drupal 5.x before 5.23 and 6.x before 6.18 does not properly support case-insensitive filename handling in a database configuration, which allows remote authenticated users to bypass the intended restrictions on downloading a file by uploading a different file with a similar name.