CVE-2026-55471

Critical

Description

HAPI FHIR is a complete implementation of the HL7 FHIR standard for healthcare interoperability in Java. Prior to 6.9.10, org.hl7.fhir.utilities.XsltUtilities saxonTransform(...) overloads instantiated a bare net.sf.saxon.TransformerFactoryImpl() without ACCESS_EXTERNAL_DTD or ACCESS_EXTERNAL_STYLESHEET restrictions, allowing an attacker who controls or can tamper with transformed XML to trigger XML External Entity injection for local file disclosure and blind XXE or SSRF to arbitrary URLs reachable from the host. This issue is fixed in version 6.9.10.

SeverityCritical

CVSS9.1

Exploit probability—

ProductHapifhir Hl7 Fhir Core

PublishedJul 8, 2026

First seenJul 8, 2026

Weakness typeCWE-611XML external entity (XXE)

How to fix

Update

hapifhir hl7_fhir_core6.9.10 or later
ca.uhn.hapi.fhir:org.hl7.fhir.utilities6.9.10 or later

Affected products

Product	Affected versions	Fixed in
hapifhir hl7_fhir_core	v < 6.9.10	6.9.10
ca.uhn.hapi.fhir:org.hl7.fhir.utilitiesMaven	v < 6.9.10	6.9.10

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