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: 0.2% (8th percentile of EPSS-scored CVEs). 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: 0.2%CVSS: 7.1Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

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
7.1HIGHmedium confidence
EG Risk
48
EG Risk 48/100CISA SSVC

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%
CISA SSVC: Track at low, Track* at medium and Attend at high mission impact.
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.2%
EPSS %ILE
8th
KEV
Not listed

CISA SSVCTrack at low, Track* at medium and Attend at high mission impact.

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

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 rangeFix by version rangeDependents
@medplum/core—
  • every version up to 5.1.6: fixed in 5.1.6
—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 13× in last 7d / 49× 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. 2026-10-05 11:54 UTCEG score recompute
  2. 2026-10-04 23:22 UTCEPSS rescore
  3. 2026-10-03 17:49 UTCEG score recompute
  4. 2026-10-03 14:26 UTCEPSS rescore
  5. 2026-10-02 17:56 UTCEPSS rescore
  6. 2026-10-02 01:35 UTCEG score recompute
  7. 2026-10-01 19:50 UTCEPSS rescore
  8. 2026-09-30 22:43 UTCEG score recompute
  9. 2026-09-30 15:03 UTCEPSS rescore
  10. 2026-09-30 10:02 UTCEG score recompute
  11. 2026-09-29 15:22 UTCEPSS rescore
  12. 2026-09-28 23:33 UTCEG score recompute
  13. 2026-09-28 13:51 UTCEPSS rescore
  14. 2026-09-27 21:43 UTCEG score recompute
  15. 2026-09-27 13:48 UTCEPSS rescore
  16. 2026-09-27 08:17 UTCEG score recompute
  17. 2026-09-26 15:59 UTCEPSS rescore
  18. 2026-09-25 02:09 UTCEG score recompute
  19. 2026-09-24 14:04 UTCEPSS rescore
  20. 2026-09-23 22:04 UTCEG score recompute
  21. 2026-09-23 17:54 UTCEPSS rescore
  22. 2026-09-22 20:41 UTCEG score recompute
  23. 2026-09-22 07:32 UTCEG score recompute
  24. 2026-09-21 06:10 UTCEG score recompute
  25. 2026-09-20 20:16 UTCEPSS rescore
Show 27 more
  1. 2026-09-20 03:18 UTCEG score recompute
  2. 2026-09-18 00:31 UTCEG score recompute
  3. 2026-09-16 23:08 UTCEG score recompute
  4. 2026-09-16 14:08 UTCEPSS rescore
  5. 2026-09-16 10:15 UTCEG score recompute
  6. 2026-09-16 05:15 UTCEPSS rescore
  7. 2026-09-15 08:35 UTCEG score recompute
  8. 2026-09-14 04:45 UTCEG score recompute
  9. 2026-09-13 16:47 UTCEPSS rescore
  10. 2026-09-13 03:23 UTCEG score recompute
  11. 2026-09-12 02:01 UTCEG score recompute
  12. 2026-09-11 14:53 UTCEPSS rescore
  13. 2026-09-11 13:19 UTCEG score recompute
  14. 2026-09-10 10:09 UTCEG score recompute
  15. 2026-09-10 09:35 UTCEPSS rescore
  16. 2026-09-09 18:29 UTCEG score recompute
  17. 2026-09-09 17:45 UTCEG score recompute
  18. 2026-09-09 03:41 UTCEG score recompute
  19. 2026-09-08 22:01 UTCEPSS rescore
  20. 2026-09-07 16:11 UTCEG score recompute
  21. 2026-09-07 16:01 UTCEPSS rescore
  22. 2026-09-07 00:45 UTCEG score recompute
  23. 2026-09-06 13:47 UTCEPSS rescore
  24. 2026-09-05 23:20 UTCEG score recompute
  25. 2026-09-04 21:54 UTCEG score recompute
  26. 2026-09-03 20:23 UTCEG score recompute
  27. 2026-08-17 13:37 UTCEG score recompute

Related CVEs(same CWE)

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 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 0.2% probability of exploitation in the next 30 days (8th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-53728?
CVE-2026-53728 has a CVSS base score of 7.1 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-53728?
A fix for CVE-2026-53728 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-53728 are linked in the Vendor Advisories panel on this page.

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