{"items":[{"id":"NVI-00015211","kind":"vulnerability","title":"Medplum: Improper Validation of Redirect URI in External Auth Callback allows Authorization Code Leakage","revision":1,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-m44r-7c5h-m6mj","CVE-2026-53728"],"plain_summary":"GitHub lists this reviewed advisory for @medplum/core. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.","review_status":"source_listed","control_topics":[],"public_actions":[{"summary":"Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.","source_ids":["sr-41800688cbbd45c686dea2ffa0f61577"],"action_type":"investigate","limitations":"Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system.","current_supported_target":null}],"schema_version":"1.1.0","source_metrics":[{"kind":"CVSS","as_of":"2026-08-17T13:36:17.000Z","value":"7.1 high","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-41800688cbbd45c686dea2ffa0f61577"}],"why_it_matters":"Published affected context helps an owner decide what evidence to gather. This report has not examined your application.","related_sources":[{"id":"sr-41800688cbbd45c686dea2ffa0f61577","url":"https://github.com/advisories/GHSA-m44r-7c5h-m6mj","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-m44r-7c5h-m6mj","publisher":"GitHub Advisory Database","observed_at":"2026-11-02T20:15:44.568Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-41800688cbbd45c686dea2ffa0f61577"],"technology":"@medplum/core","known_exclusions":[],"conditions_summary":"## Summary\n\nThe external identity provider callback at `GET /auth/external` accepts attacker-controlled redirect URIs that only need to start with a registered client redirect URI, rather than matching exactly. After a successful external IdP login, the server appends Medplum `login` and `code` values to that attacker-supplied URL and issues a redirect.\n\nBecause the external login request `state` is serialized as raw JSON and later trusted by the callback, an attacker who can tamper with `state.redirectUri` can cause Medplum to redirect authorization artifacts to an attacker-controlled endpoint. When the registered redirect URI is a bare origin or another prefix that can be extended into a different hostname, this becomes a cross-origin authorization code leak.\n\n## Technical Explanation\n\nThe vulnerable flow is exposed on the unauthenticated callback route `GET /auth/external`.\n\nIn `externalCallbackHandler()`, the server parses the external auth `state` and uses the decoded `clientId` and `redirectUri` after completing the IdP code exchange. If login succeeds and a client is found, the handler calls:\n\n- `getClientRedirectUri(client, body.redirectUri, true)`\n\nThe third argument expli","public_affected_ranges":["<= 5.1.5"]}],"null_published_at":"2026-11-03T10:03:26.561Z","source_updated_at":"2026-08-17T13:36:17.000Z","source_disclosed_at":"2026-08-17T13:36:17.000Z","is_synthetic_fixture":false,"null_last_reviewed_at":null,"public_change_summary":"First indexed by Null; source disclosure date is shown separately.","null_first_observed_at":"2026-11-02T20:15:44.568Z"}],"next_cursor":null,"snapshot_revision":"42594"}