Pathling Server in versions prior to 2.0.0 accepts an explicit oauthMetadataUrl in its bulk‑submit API without validating it against the allowed source list. The server trusts the supplied metadata, retrieves the token_endpoint from the attacker‑controlled endpoint, and builds a client‑authentication request using the submitter’s stored OAuth credentials. This flaw allows an attacker to exfiltrate those credentials or use them to obtain access tokens for downstream services. The resulting compromise threatens the confidentiality of OAuth client secrets and the resources they protect.

The vulnerability applies to Pathling Server implementations deployed by Aehrc that are running any version earlier than 2.0.0. Any system that makes bulk‑submit requests to such a server and has an allowed submitter role is at risk.

With a CVSS score of 8.7 the flaw is considered high severity. The EPSS score is not available, but the attack path requires an authorized submitter to supply a malicious oauthMetadataUrl, which is a remote vector via the bulk‑submit API. Because the server blindly trusts the returned token_endpoint, exploitation can occur without additional privileges. The vulnerability is not reported in the CISA KEV catalog, indicating no known widespread exploitation, yet the potential impact justifies proactive mitigation.