• Advisory ID: DRUPAL-SA-CORE-2009-007
  • Project: Drupal core
  • Version: 5.x, 6.x
  • Date: 2009-July-1
  • Security risk: Moderately critical
  • Exploitable from: Remote
  • Vulnerability: Multiple vulnerabilities


Multiple vulnerabilities and weaknesses were discovered in Drupal.

Cross-site scripting

The Forum module does not correctly handle certain arguments obtained from the URL. By enticing a suitably privileged user to visit a specially crafted URL, a malicious user is able to insert arbitrary HTML and script code into forum pages. Such a cross-site scripting attack may lead to the malicious user gaining administrative access. Wikipedia has more information about cross-site scripting (XSS).

This issue affects Drupal 6.x only.

Input format access bypass

User signatures have no separate input format, they use the format of the comment with which they are displayed. A user will no longer be able to edit a comment when an administrator changes the comment's input format to a format that is not accessible to the user. However they will still be able to modify their signature, which will then be processed by the new input format.

If the new format is very permissive, via their signature, the user may be able to insert arbitrary HTML and script code into pages or, when the PHP filter is enabled for the new format, execute PHP code.

This issue affects Drupal 6.x only.

Password leaked in URL

When an anonymous user fails to login due to mistyping his username or password, and the page he is on contains a sortable table, the (incorrect) username and password are included in links on the table. If the user visits these links the password may then be leaked to external sites via the HTTP referer.

In addition, if the anonymous user is enticed to visit the site via a specially crafted URL while the Drupal page cache is enabled, a malicious user might be able to retrieve the (incorrect) username and password from the page cache.

This issue affects both Drupal 5.x and Drupal 6.x

Versions affected

  • Drupal 5.x before version 5.19.
  • Drupal 6.x before version 6.13.


Install the latest version:

  • If you are running Drupal 6.x then upgrade to Drupal 6.13.
  • If you are running Drupal 5.x then upgrade to Drupal 5.19.

If you are unable to upgrade immediately, you can apply a patch to secure your installation until you are able to do a proper upgrade. Theses patches fix the security vulnerability, but do not contain other fixes which were released in Drupal 5.19 or Drupal 6.13.

Reported by

The forum XSS issue was independently reported by Mark Piper of Catalyst IT Ltd, Sven Herrmann and Brandon Knight.
The user signature issue was reported by Gerhard Killesreiter of the Drupal security team.
The password in URL issue was reported by Sumit Datta.

Fixed by

The forum XSS issue was fixed by Heine Deelstra, Peter Wolanin and Charlie Gordon.
The user signature issue was fixed by David Rothstein, Charlie Gordon, Heine Deelstra and Gábor Hojtsy.
The password in URL issue was fixed by Damien Tournoud and Bart Jansens.


The security team for Drupal can be reached at security at drupal.org or via the form at http://drupal.org/contact.