In Meari IoT Cloud MQTT Broker deployments running EMQX 4.x, any authenticated low-privilege account can subscribe to global wildcard topics and receive telemetry from devices the user does not own. The broker enforces publish restrictions but does not enforce equivalent subscribe authorization at per-device scope.

In EMQX before 5.8.6, administrators can install arbitrary novel plugins via the Dashboard web interface. NOTE: the Supplier's position is that this is the intended behavior; however, 5.8.6 adds a defense-in-depth feature in which a plugin's acceptability (for later Dashboard installation) is set by the "emqx ctl plugins allow" CLI command.

A vulnerability has been found in EMQX up to 6.2.0. This affects an unknown function of the file apps/emqx/src/emqxpersistentsessionds.erl of the component QoS 2 PUBLISH Packet Handler. Such manipulation leads to race condition. The attack may be performed from remote. A high complexity level is associated with this attack. The exploitability is reported as difficult. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure.