Elasticsearch before 1.6.1 allows remote attackers to execute arbitrary code via unspecified vectors involving the transport protocol. NOTE: ZDI appears to claim that CVE-2015-3253 and CVE-2015-5377 are the same vulnerability
https://github.com/elastic/elasticsearch/commit/bf3052d14c874aead7da8855c5fcadf5428a43f2
https://discuss.elastic.co/t/elasticsearch-remote-code-execution-cve-2015-5377/25736