Couchbase Server 7.1.x and 7.2.x before 7.2.4 does not require authentication for the /admin/stats and /admin/vitals endpoints on TCP port 8093 of localhost.
https://www.couchbase.com/alerts/
https://forums.couchbase.com/tags/security
https://docs.couchbase.com/server/current/release-notes/relnotes.html