Answer in brief
CVE-2026-53728 records a High severity (CVSS 7.1) vulnerability in Medplum - Improper Validation of Redirect URI in External Auth Callback allows Authorization Code Leakage. The current sources do not mark it as known exploited. The current feed maps medplum/medplum (generic), @medplum/core (npm), @medplum/core (npm). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps medplum/medplum (generic), @medplum/core (npm), @medplum/core (npm). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| medplum/medplumgeneric | < 5.1.6 | Not reported |
| @medplum/corenpm | <=5.1.5 | 5.1.6 |
| @medplum/corenpm | >=0 <5.1.6 | 5.1.6 |
Published upstream
Sep 3, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 3, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 17, 2026
Medplum is a developer platform that enables development of healthcare apps. Prior to version 5.1.6, the 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. Because 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. This issue has been patched in version 5.1.6.
Quoted source text, attributed separately from HOL analysis.