An XSS flaw within the user profile page has recently been discovered. This could allow an attacker to carry out an action as a user or obtain access to a user's account. To resolve this issue, it has been necessary to release a patch level version of the active versions of vBulletin.
The upgrade process is the same as previous patch level releases - simply download the patch from the Members Area, extract the files and upload to your webserver, overwriting the existing files. There is no upgrade script required.
As with all security-based releases, we recommend that all customers upgrade as soon as possible in order to prevent any potential damage resulting from the flaw being exploited.