CVE-2026-55471 HAPI FHIR: XXE in XsltUtilities.saxonTransform via unhardened Saxon TransformerFactory

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 ACCESSEXTERNALDTD or ACCESSEXTERNALSTYLESHEET...

HAPI FHIR: XXE in XsltUtilities.saxonTransform via unhardened Saxon TransformerFactory

org.hl7.fhir.utilities.XsltUtilities exposes two parallel families of XSLT transform helpers. The transform... overloads obtain their TransformerFactory from the project's hardened helper XMLUtil.newXXEProtectedTransformerFactory which sets ACCESSEXTERNALDTD="" and ACCESSEXTERNALSTYLESHEET="". Th...