A reflected cross-site scripting (XSS) vulnerability exists in the authentication endpoint of multiple WSO2 products due to missing output encoding of user-supplied input. A malicious actor can exploit this vulnerability to inject arbitrary JavaScript into the authentication flow, potentially leading to UI modifications, redirections to malicious websites, or data exfiltration from the browser. While this issue could allow an attacker to manipulate the user’s browser, session-related sensitive cookies remain protected with the httpOnly flag, preventing session hijacking.