This tweet describes a security issue involving a basic Cross-Site Scripting (XSS) vulnerability that is used to bypass a Web Application Firewall (WAF). The attack chain then leads to stealing an OAuth code, which ultimately results in an account takeover. Although the tweet does not provide specific details about the WAF vendor or the payload used for the bypass, it highlights a critical exploitation sequence where an initial XSS vulnerability is leveraged to bypass security defenses and escalate the attack into a full account compromise. This emphasizes the importance of not only protecting against XSS vulnerabilities but also ensuring that WAFs are robust enough to prevent such bypasses. The mention of an OAuth code theft suggests that the attacker can impersonate users and gain unauthorized access to their accounts, which poses serious security risks. This bug chain showcases how a seemingly simple XSS flaw can be part of a dangerous multi-step attack.