CVE-2026-126473: OpenEMR before 8.4.0 OAuth Authorization Bypass via Scope Canonicalization

Is it exploited?

Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of 13 Nov 2026. If CISA adds it, this page shows it as known exploited.

How likely is exploitation in the next 30 days?

0.5%

EPSS score, percentile 40.5 of all scored records. A probability estimated by FIRST, not a report of exploitation.

CISA's SSVC assessment in the CVE record lists exploitation as poc.

How severe?

9.3 Critical

CVSS v4.0 base score, given by the CNA

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

Advisories and patches (1)

Which versions are affected?

Affected

• before 8.4.0

Unaffected 8.4.0

Versions by product

Source: CISA KEV 2026.11.13, as of 13 Nov 2026; FIRST EPSS, as of 13 Nov 2026; CVE List, as of 14 Nov 2026. About the data.

Description

OpenEMR before 8.4.0 OAuth Authorization Bypass via Scope Canonicalization

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.

Source: CVE List, as of 14 Nov 2026. About the data.

What to do

Advisories and patches

• GitHub Security Advisory (GHSA-6xh3-fmm5-jjp4) (Vendor advisory)

This summary is based on the CVE record as of 14 Nov 2026. Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

Source: CVE List, as of 14 Nov 2026. About the data.

Timeline