An issue was found with how API keys are created with the Fleet-Server service account. When an API key is created with a service account, it is possible that the API key could be created with higher privileges than intended. Using this vulnerability, a compromised Fleet-Server service account could escalate themselves to a super-user.
https://www.elastic.co/community/security
https://discuss.elastic.co/t/elastic-stack-7-14-1-security-update/283077