Meshtastic is an open source, off-grid, decentralized, mesh network. Meshtastic uses MQTT to communicate over an internet connection to a shared or private MQTT Server. Nodes can communicate directly via an internet connection or proxied through a connected phone (i.e., via bluetooth). Prior to version 2.5.1, multiple weaknesses in the MQTT implementation allow for authentication and authorization bypasses resulting in unauthorized control of MQTT-connected nodes. Version 2.5.1 contains a patch.