SEPTEMBER 17, 2026
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Case File

CVE-2026-53728

HIGH · CVSS 7.1 EPSS 0.14% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-09-03 · Last synced 2026-09-17

CyberRota Analysis

AI-Generated

Medplum's external identity provider callback prior to version 5.1.6 is vulnerable to an attack that allows unauthorized redirection of authorization artifacts to attacker-controlled endpoints due to improper validation of redirect URIs. This flaw can lead to cross-origin authorization code leakage, potentially compromising sensitive user data. Healthcare app developers using Medplum should prioritize upgrading to version 5.1.6 to mitigate this high-severity vulnerability.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

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CVE
CVE-2026-53728
Severity
HIGH
CVSS
7.1
EPSS
0.14%

Original NVD Description

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.