It was found that Apache Solr would accept an object from an unauthenticated user that could be manipulated through subsequent post requests. An attacker could use this flaw to assemble an object that could permit execution of arbitrary code on the server.
A flaw was found in the Apache Solr's Config API, where it would permit the configuration of the JMX server via an HTTP POST request. An attacker could use this flaw to direct traffic to a malicious RMI server, and then trigger remote code execution or conduct further attacks.