Telenor security executive Tor Indstøy tracked a NIO ES8 SUV for several years under a study called Project Lion Cage. The research found 90% of the vehicle's connections routed to Chinese servers, including instances where the car was switched off and isolated inside a mine. Most of the transmitted traffic was encrypted, which allowed researchers to identify the destination of the data but not its specific content.

The findings contradict NIO's claims to European customers that their data is processed within Europe. A separate trial by Oslo transit operator Ruter determined that the maker of Yutong buses can access battery and power systems through software updates, though Yutong denies it can control steering or brakes. China's National Intelligence Law requires companies to assist state intelligence work.