The Google Glass developer claims a security flaw in the early version could allow hackers to control the device remotely.
Software developer Jay Freeman blogged about his discovery of an "in" for hackers to plant software on Glass to spy on its user.
"They have control over a camera and a microphone that are attached to your head," Freeman told Huffington Post. "A bugged Glass doesn't just watch your every move: it watches everything you are looking at ... and hears everything you do. The only thing it doesn't know are your thoughts."
Freeman also said the current version of Glass doesn't have a PIN code to lock the device, making it that much easier for hackers to install malware and steal users passwords.
According to HuffPost, Twitter security's Charlie Miller said this weakness would be hard for a hacker to exploit since the user would have to leave the device unattended for several minutes for the malware to be installed.
Google said Glass is still a work in progress and is not read for public use.