vBulletin 4.0.2 Patch Level 1 has been released.
An XSS exploit has been discovered in 4.0.1 and 4.0.2. It is strongly recommend that anyone running these versions immediately patch their systems.
Read more / Get it at: vbulletin.com/forum/showthread.php?342962-vBulletin-4.0.2-Patch-Level-1-Released