CVE-2026-126473

CRITICAL 9.1

OpenEMR before 8.4.0 OAuth Authorization Bypass via Scope Canonicalization

CVSS Score

9.1

EPSS Score

0.0%

EPSS Percentile

0th

OpenEMR before 8.4.0 contains OAuth scope canonicalization and containment flaws that allow unauthenticated attackers to obtain unapproved system-level FHIR access. Attackers can register a colon-form system:Patient.read client that bypasses approval, then request unregistered system/Patient.write scope to read, modify, and create Patient records.

CWE	CWE-863
Vendor	openemr
Product	openemr
Published	Nov 13, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

None

Affected Versions

openemr / openemr

0 < 8.4.0

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/openemr/openemr/security/advisories/GHSA-6xh3-fmm5-jjp4 vulncheck.com: https://www.vulncheck.com/advisories/openemr-before-8.4.0-oauth-authorization-bypass-via-scope-canonicalization

Credits

🔍 mcspicyenjoyer