vBulletin has released 3.7.7 and 4.0.2 PL 2, which is Security fix releases
The vBulletin development team has identified a potential issue with the strength of password encryption in vBulletin and we are implementing a patch to address this issue.
Read more / Get it at: vbulletin.com/forum/showthread.php?346486-Security-Fix-Releases-3.7.7-and-4.0.2-PL-2
Please not that I am not sure if this is the patch I wrote about here, so it might be wise to check it out as well.