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.

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.

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.

Cross-site scripting (XSS) vulnerability in the Locale module (modules/locale/locale.module) in Drupal Core 6.14, and possibly other versions including 6.15, allows remote authenticated users with "administer languages" permissions to inject arbitrary web script or HTML via the (1) Language name in English or (2) Native language name fields in the Custom language form.