CVE-2026-44506

Medplum prior to version 5.1.6 has a vulnerability in the external identity provider callback at GET /auth/external that accepts attacker-controlled redirect URIs that only need to start with a registered client redirect URI. After a successful external IdP login, the server appends Medplum login and code values to that attacker-supplied URL and issues a redirect. Because the external login request state is serialized as raw JSON and later trusted, an attacker who can tamper with state.redirectUri can cause Medplum to redirect authorization artifacts to an attacker-controlled endpoint, leading to a cross-origin authorization code leak. This issue has been patched in version 5.1.6.

Medplum before version 5.1.14 has an SSRF vulnerability in the subscription worker, allowing authenticated users to perform unauthorized network requests by creating FHIR Subscription resources with arbitrary endpoint URLs. Attackers can point subscriptions at internal addresses like cloud metadata services, databases, or container orchestration endpoints to exfiltrate IAM credentials and patient health records.