Drupal Context Module XSS
Description of Vulnerability:
Drupal (http://drupal.org) is a robust content management system (CMS) written in PHP and MySQL. The Drupal Context module (http://drupal.org/project/context) "allows you to manage contextual conditions and reactions for different portions of your site." The Context module contains a cross site scripting (XSS) vulnerability because it fails to sanitize block descriptions before display.
Drupal 6.16 with Context 6.x-2.0-rc3 was tested and shown to be vulnerable.
User could inject arbitrary scripts into pages affecting site users. This could result in administrative account compromise leading to web server process compromise.
In order to execute arbitrary script injection malicious users must have 'Administer blocks' permission.
Technical discussion and proof of concept:
Users with 'administer blocks' permission can insert arbitrary script in block descriptions which is rendered by the Context module at ?q=admin/build/context/X where X is the block id.