`org.hl7.fhir.core` XXE vulnerability in XSLT transforms

The HL7 FHIR Core Artifacts repository provides the java core object handling code, with utilities (including validator), for the Fast Healthcare Interoperability Resources (FHIR) specification. Prior to version 6.3.23, XSLT transforms performed by various components are vulnerable to XML external entity injections. A processed XML file with a malicious DTD tag could produce XML containing data from the host system. This impacts use cases where org.hl7.fhir.core is being used to within a host where external clients can submit XML. This issue has been patched in release 6.3.23. No known workarounds are available.