The JMX RMI service in VMware vCenter Server 5.0 before u3e, 5.1 before u3b, 5.5 before u3, and 6.0 before u1 does not restrict registration of MBeans, which allows remote attackers to execute arbitrary code via the RMI protocol.
http://www.zerodayinitiative.com/advisories/ZDI-15-455
http://www.vmware.com/security/advisories/VMSA-2015-0007.html
http://www.securitytracker.com/id/1033720