Summary:
Elasticsearch versions 1.3.x and prior have a default configuration for
CORS that allows an attacker to craft links that could cause a user’s
browser to send requests to Elasticsearch instances on their local network.
These requests could cause data loss or compromise.

We have been assigned CVE-2014-6439 for this issue.


Fixed versions:
Version 1.4.0 beta 1 and later change the default configuration.


Remediation:
Users should either set “http.cors.enabled” to false, or set
“http.cors.allow-origin” to the value of the server that should be allowed
access, such as localhost or a server hosting Kibana.  Disabling CORS
entirely with the former setting is more secure, but may not be suitable
for all use cases.

CVSS
Overall CVSS score: 5.3

More information:
http://www.elasticsearch.org/blog/elasticsearch-1-4-0-beta-released/