CVE-2026-53728

HIGHPre-NVD 7.17.1—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.1%, top 96% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Elevated
7.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.1Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
7.1
EG Score
7.1(medium)
EG Risk
48(Track*)
EG Risk 48/100SSVC: Track*

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity71% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Watch closely — could escalate to Attend.
EPSS PROB
0%
EPSS %ILE
4%
KEV
Not listed

Published

August 17, 2026

Last Modified

September 9, 2026

Advisory Details (4)

Auto-updated Sep 3, 2026
Patch available. Sources: github, github_pr, github_commit, github_release.
github_release Patch Available

Version 5.1.6

Patch available: medplum/medplum v5.1.6

https://github.com/medplum/medplum/releases/tag/v5.1.6
github_commit

commit 7ae10035ddad (medplum/medplum)

Fix landed in medplum/medplum commit 7ae10035ddad — awaiting tagged release

https://github.com/medplum/medplum/commit/7ae10035ddadde4dba7b18d3156553940465b3a1
github_pr

Disable redirect URL partial match

Fix merged in medplum/medplum PR #8749 on 2026-03-31 — awaiting tagged release

https://github.com/medplum/medplum/pull/8749
github Patch Available

Medplum - Improper Validation of Redirect URI in External Auth Callback allows Authorization Code Leakage · Advisory · medplum/medplum · GitHub

https://github.com/medplum/medplum/security/advisories/GHSA-m44r-7c5h-m6mj

Vendor Advisories for CVE-2026-53728(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFixed inDependents
@medplum/core—5.1.6—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 9× in last 7d / 25× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-18 00:31 UTCEG score recompute
  2. 2026-09-16 23:08 UTCEG score recompute
  3. 2026-09-16 14:08 UTCEPSS rescore
  4. 2026-09-16 10:15 UTCEG score recompute
  5. 2026-09-16 05:15 UTCEPSS rescore
  6. 2026-09-15 08:35 UTCEG score recompute
  7. 2026-09-14 04:45 UTCEG score recompute
  8. 2026-09-13 16:47 UTCEPSS rescore
  9. 2026-09-13 03:23 UTCEG score recompute
  10. 2026-09-12 02:01 UTCEG score recompute
  11. 2026-09-11 14:53 UTCEPSS rescore
  12. 2026-09-11 13:19 UTCEG score recompute
  13. 2026-09-10 10:09 UTCEG score recompute
  14. 2026-09-10 09:35 UTCEPSS rescore
  15. 2026-09-09 18:29 UTCEG score recompute
  16. 2026-09-09 17:45 UTCEG score recompute
  17. 2026-09-09 03:41 UTCEG score recompute
  18. 2026-09-08 22:01 UTCEPSS rescore
  19. 2026-09-07 16:11 UTCEG score recompute
  20. 2026-09-07 16:01 UTCEPSS rescore
  21. 2026-09-07 00:45 UTCEG score recompute
  22. 2026-09-06 13:47 UTCEPSS rescore
  23. 2026-09-05 23:20 UTCEG score recompute
  24. 2026-09-04 21:54 UTCEG score recompute
  25. 2026-09-03 20:23 UTCEG score recompute
Show 1 more
  1. 2026-08-17 13:37 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-53728?
CVE-2026-53728 is a high vulnerability published on August 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.…
When was CVE-2026-53728 disclosed?
CVE-2026-53728 was first published in the National Vulnerability Database on August 17, 2026, with the most recent update on September 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-53728 actively exploited?
CVE-2026-53728 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 96.4% of all scored CVEs.
What is the CVSS score of CVE-2026-53728?
CVE-2026-53728 has a CVSS v3 base score of 7.1 (NVD).
How do I remediate CVE-2026-53728?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-53728, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-53728

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