Google Secretly Installs LLM in Chrome Browser Without User Permission

May 8, 2026

Security researcher Alexander Hanff discovered that Google Chrome secretly installed the four-gigabyte Gemini Nano LLM on users' devices without permission, stored in an OptGuideOnDeviceModel folder with a weights.bin file. The model provides advanced auto-correct and text suggestion features through in-browser APIs. Chrome users reported slower performance and hefty disk access after installation.

Chrome LLM installation

▪Chrome users noticed slower performance and hefty disk access after the LLM installation.
▪Chrome is by far the most popular web browser.
▪The Chrome LLM will be used to provide advanced auto-correct and text suggestion features.
▪Google installed an LLM as part of the Chrome browser without user knowledge.
▪The Gemini Nano model installed in Chrome is four gigabytes in size.
▪The Chrome LLM is available through a set of in-browser APIs.

Global power consumption increase

▪The installation of an extremely energy intensive LLM on billions of computers will have a significant effect on global power consumption.
▪The Chrome LLM installation will cause a consequent uptick in the carbon footprint of computing.

User consent violations

▪Chrome users cannot use the installed LLM for anything except what Google Chrome wants it to be used for.
▪The Chrome LLM is not under user control and is ultimately controlled by Google.
▪The Chrome LLM has been installed without user consent.

Local LLM alternatives

▪Siri has used a local LLM on Apple devices for a while.
▪Usage data from Llama.cpp is not sold to third parties.
▪Llama.cpp is a local LLM that users can install on their own machine.

Opt-in software models

▪A user-controlled local LLM could make its services available to applications such as a web browser if the user allows it to.
▪A user-controlled local LLM should not run unless asked by the user.

Perspective of Privacy and security advocates (represented by Alexander Hanff)

▪A user-controlled local LLM should not run unless asked by the user and should make its services available to applications only if the user allows it.