SQL injection vulnerability in vBulletin 5.0.4 through 5.1.3 Alpha 5 allows remote attackers to execute arbitrary SQL commands via the criteria[startswith] parameter to ajax/render/memberlistitems.

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 5.x through 5.1.6 allows remote authenticated users to bypass authorization checks and inject private messages into conversations via vectors related to an input validation failure.