As you may know, Drupal 6 has reached End-of-Life (EOL) which means the Drupal Security Team is no longer doing Security Advisories or working on security patches for Drupal 6 core or contrib modules - but the Drupal 6 LTS vendors are and we're one of them!
Today, there is a Moderately Critical security release for the Site Verify module to fix an Cross Site Scripting (XSS) vulnerability.
The Site Verify module enables privilege users to verify a site with services like Google Webmaster Tools using meta tags or file uploads.
The module doesn't sufficiently sanitize input or restrict uploads.
See the security advisory for Drupal 7 for more information.
Here you can download the Drupal 6 patch.
If you have a Drupal 6 site using the Site Verify module, we recommend you update immediately.
If you'd like all your Drupal 6 modules to receive security updates and have the fixes deployed the same day they're released, please check out our D6LTS plans.
Note: if you use the myDropWizard module (totally free!), you'll be alerted to these and any future security updates, and will be able to use drush to install them (even though they won't necessarily have a release on Drupal.org).