Header Injection via Custom URL Configuration in Multiple WSO2 Products Allows Open Redirect and Log Forgery

When a proxy server is configured with `customUrl.enabled`, the component accepts user-supplied input within forwarded HTTP headers without enforcing expected validation constraints. A malicious actor can manipulate these headers to influence the URL construction process, leading to an open redirect vulnerability. Additionally, unsanitized header values are written to application logs.

An attacker can exploit this to force redirection to arbitrary malicious domains, potentially enabling phishing attacks. Furthermore, they can inject forged entries into application logs, impacting the reliability of security logs and potentially hindering incident investigation.