The team is excited to announce the release of CiviCRM 3.3.5 - it is now available for download. You can also try it out on our demo site. Apart from fixing a few bug issues, this release contains two critical security updates:
Cross site scripting problem, where the site can be exploited to execute arbitrary JavaScript. Permissioning vulnerability, which allowed anonymous users to potentially change information for another contact.
Please consider doing an upgrade as soon as possible to avoid potential security risks. If you have already upgraded using the 3.3.4 release package - and you did not experience any errors during the upgrade - then you already have the security patches installed and you do not have to upgrade to this release at this time.