In MobaXterm 11.1 and 12.1, the protocol handler is vulnerable to command injection. A crafted link can trigger a popup asking whether the user wants to run MobaXterm to handle the link. If accepted, another popup appears asking for further confirmation. If this is also accepted, command execution is achieved, as demonstrated by the MobaXterm://`calc` URI.
https://freetom.github.io/0day/2019/09/14/MobaXterm-command-exec-in-protocol-handler.html