In Elastic Cloud Enterprise (ECE) versions prior to 1.1.4 it was discovered that a user could scale out allocators on new hosts with an invalid roles token. An attacker with access to the previous runner ID and IP address of the coordinator-host could add a allocator to an existing ECE install to gain access to other clusters data.
https://www.elastic.co/community/security
https://discuss.elastic.co/t/elastic-cloud-enterprise-1-1-4-security-update/135778