An issue in MongoDB Server could allow an authenticated user with a limited database-scoped role to perform an action against protected system collections that their assigned privileges should not permit. This could result in critical system collections being dropped and recreated without proper authorization.
An issue in MongoDB Server's intra-cluster connection setup could allow a party with suitable network access to influence which authentication mechanism is used when one replica set member connects to another. Under certain conditions, this could cause the cluster's shared internal credential to be transmitted in a less-protected form, potentially allowing that credential to be recovered. If recovered, the credential could be used to authenticate as the internal superuser to nodes in the deployment.