Lookout has started security testing the Google Glass product. They have discovered a vulnerability with QR codes. They have submitted this vulnerability to Google and Google has mitigated it. This has opened some peoples eyes to more vulnerabilities that it may have.
This particular exploit would be able to use either a printed QR code or a blue tooth device to send the code to the Google Glass. With the blue tooth exploit you would need to have physical access once to pair the device. This is still really easy when all you have to do is tap the glass to pair the device.
This QR code attack makes your Google Glass run code, this code has been able to turn on your camera to where others can see what you are looking at. The codes have also been able to make you Google Glass browse to any web page that they specify.
These attacks are good to know about long before a product like this goes public. This way Google will be able to narrow the attack surface of there Glass and other products that may share similar software.