CVE-2026-53728
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.
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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.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:L
- Puntuación base: 7.1
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.20%
- Percentil entre todas las CVEs puntuadas: 9
- Fecha de la puntuación: 4/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
🎯 Técnicas ATT&CK
Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.
- Explotación
T1189Drive-by Compromiseinitial access85 % - Impacto principal
T1598.002Spearphishing Attachmentreconnaissance80 % - Impacto secundario
T1204.001Malicious Linkexecution70 %
XSS/Open Redirect en callback OAuth: UI:R + ataque a través de enlace malicioso manipulando redirectUri. Impacto: phishing (T1598.002) y ejecución de código en cliente (T1204.001) al seguir enlace adversario.
Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.
🛡️ Mitigaciones ATT&CK que cubren estas técnicas
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
CWE
- CWE-345, CWE-601
Referencias
- https://github.com/medplum/medplum/commit/7ae10035ddadde4dba7b18d3156553940465b3a1
- https://github.com/medplum/medplum/pull/8749
- https://github.com/medplum/medplum/releases/tag/v5.1.6
- https://github.com/medplum/medplum/security/advisories/GHSA-m44r-7c5h-m6mj
- https://github.com/medplum/medplum/security/advisories/GHSA-m44r-7c5h-m6mj
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-53728",
"cveTags": [],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-53728",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "poc"
},
{
"automatable": "no"
},
{
"technicalImpact": "total"
}
],
"version": "2.0.3",
"timestamp": "2026-09-09T17:40:46.117469Z"
}
}
],
"cvssMetricV31": [
{
"type": "Secondary",
"source": "security-advisories@github.com",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 7.1,
"attackVector": "NETWORK",
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:L",
"integrityImpact": "HIGH",
"userInteraction": "REQUIRED",
"attackComplexity": "HIGH",
"availabilityImpact": "LOW",
"privilegesRequired": "NONE",
"confidentialityImpact": "HIGH"
},
"impactScore": 5.5,
"exploitabilityScore": 1.6
}
]
},
"affected": [
{
"source": "security-advisories@github.com",
"affectedData": [
{
"vendor": "medplum",
"product": "medplum",
"versions": [
{
"status": "affected",
"version": "< 5.1.6"
}
]
}
]
}
],
"published": "2026-09-03T20:17:21.643",
"references": [
{
"url": "https://github.com/medplum/medplum/commit/7ae10035ddadde4dba7b18d3156553940465b3a1",
"source": "security-advisories@github.com"
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{
"url": "https://github.com/medplum/medplum/pull/8749",
"source": "security-advisories@github.com"
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{
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"source": "security-advisories@github.com"
},
{
"url": "https://github.com/medplum/medplum/security/advisories/GHSA-m44r-7c5h-m6mj",
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/medplum/medplum/security/advisories/GHSA-m44r-7c5h-m6mj",
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
}
],
"vulnStatus": "Deferred",
"weaknesses": [
{
"type": "Secondary",
"source": "security-advisories@github.com",
"description": [
{
"lang": "en",
"value": "CWE-345"
},
{
"lang": "en",
"value": "CWE-601"
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}
],
"descriptions": [
{
"lang": "en",
"value": "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."
}
],
"lastModified": "2026-09-09T21:09:13.080",
"sourceIdentifier": "security-advisories@github.com"
}