Description
Elasticsearch versions 7.0.0-7.3.2 and 6.7.0-6.8.3 contain a username disclosure flaw was found in the API Key service. An unauthenticated attacker could send a specially crafted request and determine if a username exists in the Elasticsearch native realm.
Remediation
References
https://discuss.elastic.co/t/elastic-stack-6-8-4-security-update/204908
https://discuss.elastic.co/t/elastic-stack-7-4-0-security-update/201831
https://www.elastic.co/community/security