An issue was discovered in Couchbase Server 6.6.x through 7.2.0, before 7.1.5 and 7.2.1. Unauthenticated users may cause memcached to run out of memory via large commands.
https://www.couchbase.com/downloads
https://www.couchbase.com/alerts/
https://forums.couchbase.com/tags/security
https://docs.couchbase.com/server/current/release-notes/relnotes.html