If the MongoDB Server running on Windows or macOS is configured to use TLS with a specific set of configuration options that are already known to work securely in other platforms (e.g. Linux), it is possible that client certificate validation may not be in effect, potentially allowing client to establish a TLS connection with the server that supplies any certificate. This issue affect all MongoDB Server v6.3 versions, MongoDB Server v5.0 versions v5.0.0 to v5.0.14 and all MongoDB Server v4.4 versions.

It may be possible to have an extremely long aggregation pipeline in conjunction with a specific stage/operator and cause a stack overflow due to the size of the stack frames used by that stage. If an attacker could cause such an aggregation to occur, they could maliciously crash MongoDB in a DoS attack. This vulnerability affects MongoDB Server v4.4 versions prior to and including 4.4.28, MongoDB Server v5.0 versions prior to 5.0.4 and MongoDB Server v4.2 versions prior to 4.2.16. Workaround: >= v4.2.16 users and all v4.4 users can add the --setParameter internalPipelineLengthLimit=50 instead of the default 1000 to mongod at startup to prevent a crash.

MongoDB on Red Hat Satellite 6 allows local users to bypass authentication by logging in with an empty password and delete information which can cause a Denial of Service.