I was involved in the creation of the Arduino CEC library, so I instantly recognized the schematic included in the PDF on page 17. My hardware implementation of interface is here: <a href="http://www.andrewncarr.com/hdmi/" rel="nofollow">http://www.andrewncarr.com/hdmi/</a> (I included additional wiring for hotplug detection and an EDID interface)<p>It has been great to see the progress in the 2.5 years since, with LibCEC and availability of commercial adapters. As far as I know, no discrete video card yet offers access to the CEC bus.<p>I'm not sure what security vulnerabilities are possible via CEC, no vectors that I can see, but I am no Moxie Marlinspike. I suppose newer sets may store things like Netflix credentials, but CEC is often implemented in a discrete chip, or embedded port controller. That was the state of things in 2008 models anyway, and it is a fast moving area, so I am likely way out of date. The OSD "internet features" of my 2008 Samsung are laughably quaint compared to what budget models can do today.