An issue was discovered in Couchbase Server 6.5.x and 6.6.x before 6.6.6, 7.x before 7.0.5, and 7.1.x before 7.1.2. During the start-up of a Couchbase Server node, there is a small window of time (before the cluster management authentication has started) where an attacker can connect to the cluster manager using default credentials.