Apache NiFi JMS Deserialization issue because of ActiveMQ client vulnerability. Malicious JMS content could cause denial of service. See ActiveMQ CVE-2015-5254 announcement for more information. The fix to upgrade the activemq-client library to 5.15.3 was applied on the Apache NiFi 1.6.0 release. Users running a prior 1.x release should upgrade to the appropriate release.