A flaw was discovered in Elasticsearch affecting the search API that allowed a specially crafted query string to cause a stack overflow and ultimately a denial of service.

An issue has been identified with how Elasticsearch handled incoming requests on the HTTP layer. An unauthenticated user could force an Elasticsearch node to exit with an OutOfMemory error by sending a moderate number of malformed HTTP requests. The issue was identified by Elastic Engineering and we have no indication that the issue is known or that it is being exploited in the wild.

Elasticsearch could allow a local authenticated attacker to obtain sensitive information, caused by the insertion of sensitive information into the log files. By leveraging the deprecated xpack/security API, an attacker could exploit this vulnerability to obtain sensitive information, and use this information to launch further attacks against the affected system.