Certain vBulletin versions might allow attackers to execute arbitrary PHP code by abusing Template Conditionals in the template engine. By crafting template code in an alternative PHP function invocation syntax, such as the var_dump(test) syntax, attackers can bypass security checks and execute arbitrary PHP code, as exploited in the wild in May 2025.
The product does not sufficiently protect all possible paths that a user can take to access restricted functionality or resources.