Visiting a specially crafted page, anywhere on the web, may
allow that page to post forms to a Drupal site in the
context of the visitor's session. To illustrate; suppose
one has an active user 1 session, the most powerful
administrator account for a site, to a Drupal site while
visiting a website created by an attacker. This website
will now be able to submit any form to the Drupal site with
the privileges of user 1, either by enticing the user to
submit a form or by automated means.
An attacker can exploit this vulnerability by changing
passwords, posting PHP code or creating new users, for
example. The attack is only limited by the privileges of
the session it executes in.