A remote code execution vulnerability exists in MapR CLDB code, specifically in the JSON framework that is used in the CLDB code that handles login and ticket issuance. An attacker can use the 'class' property of the JSON request sent to the CLDB to influence the JSON library's decision on which Java class this JSON request is deserialized to. By doing so, the attacker can force the MapR CLDB to construct a URLClassLoader which loads a malicious Java class from a remote path and instantiate this object in the MapR CLDB, thus executing arbitrary code on the machine running the MapR CLDB and take over the cluster. By switching to the newer Jackson library and ensuring that all incoming JSON requests are only deserialized to the same class that it was serialized from, the vulnerability is fix