The file upload feature in Drupal 6.x before 6.27 and 7.x before 7.18 allows remote authenticated users to bypass the protection mechanism and execute arbitrary PHP code via a null byte in a file name.

Drupal 6.x before 6.27 and 7.x before 7.18 displays information for blocked users, which might allow remote attackers to obtain sensitive information by reading the search results.

Drupal 6.x before 6.27 allows remote attackers to obtain sensitive information about uploaded files via a (1) RSS feed or (2) search result.

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 OpenID module in Drupal 6.x before 6.18, and the OpenID module 5.x before 5.x-1.4 for Drupal, violates the OpenID 2.0 protocol by not checking for reuse of openid.response_nonce values, which allows remote attackers to bypass authentication by leveraging an assertion from an OpenID provider.

The OpenID module in Drupal 6.x before 6.18, and the OpenID module 5.x before 5.x-1.4 for Drupal, violates the OpenID 2.0 protocol by not verifying the openid.return_to value, which allows remote attackers to bypass authentication by leveraging an assertion from an OpenID provider.

The OpenID module in Drupal 6.x before 6.18, and the OpenID module 5.x before 5.x-1.4 for Drupal, violates the OpenID 2.0 protocol by not ensuring that fields are signed, which allows remote attackers to bypass authentication by leveraging an assertion from an OpenID provider.

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.

Multiple cross-site scripting (XSS) vulnerabilities in Drupal 6.x before 6.18 allow remote authenticated users with certain privileges to inject arbitrary web script or HTML via (1) an action description, (2) an action message, (3) a node, or (4) a taxonomy term, related to the actions feature and the trigger module.