Cisco released four separate security advisories today to warn of the risks and urge TelePresence users to deploy patches, especially in sensitive business environments. (more)
Advisory 3
Advisory 4
Of course...
• Don't set up any teleconferencing system outside of your firewall.
• Don't turn the auto-answer feature on.
• Don't forget to set "mute mic" as a default.
In fact, just shut the whole thing off until you need it.