Don't Call That "Protected" Method: Dissecting an N-Day vBulletin RCE

vBulletin is one of the most widely used commercial forum solutions over the Internet, powering thousands of online communities ranging from niche hobbyist sites to large-scale tech forums. Developed primarily in PHP, it features a custom MVC-like framework and a proprietary API system designed to handle AJAX and mobile app interactions. Over the years, vBulletin has gained a reputation for both…