Ucum-java is a FHIR Java library providing UCUM Services. In versions prior to 1.0.9, XML parsing performed by the UcumEssenceService is 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 ucum is being used to within a host where external clients can submit XML. Release 1.0.9 of Ucum-java fixes this vulnerability. As a workaround, ensure that the source xml for instantiating UcumEssenceService is trusted.