The LiteLLM proxy's /sso/debug/callback endpoint is vulnerable to reflected cross-site scripting (XSS) due to improper handling of identity-provider-controlled fields in an inline script block. An attacker can inject a string containing </script> to break out of the script context and execute arbitrary JavaScript in the proxy's origin. This endpoint requires no authentication, allowing attackers with an account on the configured identity provider to craft malicious callback URLs that, when visited by a logged-in proxy admin, can lead to session cookie theft and full admin account takeover.