vBulletin 3.7.4 PL1
An XSS flaw within the user control panel 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 is necessary to release a patch level version of vBulletin 3.7.4.
vBulletin 3.6 is not affected. vBulletin 3.8 is affected, and the next beta/release candidate will include the fix.
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.
Upgrading from 3.7.4
If you are already running 3.7.4, the process you will be required to follow to make your board immune to this flaw is very simple.
There is no need to run an upgrade script if you are already running 3.7.4.
Visit the
Patches section of the vBulletin Members' Area and download the patch for 3.7.4, then extract the files from the archive you downloaded, then upload the files to your board via FTP etc., overwriting the existing files. This will update your version to the PL1 release.
Upgrading from Versions Earlier than 3.7.4
If you are
not already running 3.7.4, you should download the latest version from the
Members' Area and perform an upgrade as normal.
Full instructions for upgrading vBulletin are available here. Download vBulletin 3.7.4 PL1
As usual, the version released today is available for all customers with valid, active licenses to download from the vBulletin Members' Area.
vBulletin Members Area
You can discuss this patch release in the existing
3.7.4 release discussion.
More... 
vBulletin 3.7.4 PL1 Released 
