Cross-site scripting (XSS) vulnerability in admincp/apilog.php in vBulletin 4.2.2 and earlier, and 5.0.x through 5.0.5 allows remote authenticated users to inject arbitrary web script or HTML via a crafted XMLRPC API request, as demonstrated using the client name.
The vBApiHook::decodeArguments method in vBulletin 5 Connect 5.1.2 through 5.1.9 allows remote attackers to conduct PHP object injection attacks and execute arbitrary PHP code via a crafted serialized object in the arguments parameter to ajax/api/hook/decodeArguments.
vBulletin before 5.5.6pl1, 5.6.0 before 5.6.0pl1, and 5.6.1 before 5.6.1pl1 has incorrect access control.