Drupal is a free and open-source content-management framework written in PHP and distributed under the GNU General Public License. It is used as a back-end framework for at least 2.1% of all Web sites worldwide.According to Security advisories, Password reset URLs can be forged under certain circumstances, allowing an attacker to gain access to another user's account without knowing the account's password.
In Drupal 7, this vulnerability is mitigated by the fact that it can only be exploited on sites where accounts have been imported or programmatically edited in a way that results in the password hash in the database being the same for multiple user accounts.
In Drupal 6, it can additionally be exploited on sites where administrators have created multiple new user accounts with the same password via the administrative interface, or where accounts have been imported or programmatically edited in a way that results in the password hash in the database being empty for at least one user account.
Drupal 6 sites that have empty password hashes, or a password field with a guessable string in the database, are especially prone to this vulnerability. This could apply to sites that use external authentication so that the password field is set to a fixed, invalid value.
Drupal core and contributed modules frequently use a "destination" query string parameter in URLs to redirect users to a new destination after completing an action on the current page.
This vulnerability is mitigated by the fact that many common uses of the "destination" parameter are not susceptible to the attack. However, all confirmation forms built using Drupal 7's form API are vulnerable via the Cancel action that appears at the bottom of the form, and some Drupal 6 confirmation forms are vulnerable too.
Drupal released the Patch security vulnerabilities. Sites are urged to upgrade immediately. No changes have been made to the .htaccess, web.config, robots.txt or default settings.php files in this release, so upgrading custom versions of those files is not necessary.
