An access control issue in MobaXterm before v22.1 allows attackers to make connections to the server via the SSH or SFTP protocols without authentication.
When aborting a SFTP connection, MobaXterm before v22.1 sends a hardcoded password to the server. The server treats this as an invalid login attempt which can result in a Denial of Service (DoS) for the user if services like fail2ban are used.