What Browser Extensions Know About You — and How to Limit It
Direct answer: a browser extension can read everything on the pages you open, see what you type into forms on those pages, and watch where you browse — depending only on the permissions you granted it. Limiting that exposure comes down to three habits: grant permissions narrowly, audit what you have installed, and keep sensitive accounts in a clean profile with the fewest extensions possible.
What permissions actually mean
An extension that asks to "read and change all your data on all websites" is asking for the keys to every page you visit — including your email inbox, your banking session, and your admin panels. Some tools genuinely need broad access to work. Most do not. When an extension asks for the whole web and its job is one website, that mismatch is the tell.
The audit that takes ten minutes
Open your browser's extension list and, for each entry, ask three questions: Do I remember installing this? Do I still use it? Does its requested access match its job? Remove anything that fails a question. For the survivors, check whether the same function exists as a narrower permission — many browsers now let you scope an extension to specific sites.
Where AI features change the picture
AI-powered tools add a second question: where does the processing happen? A summarizer that works entirely on your device keeps your page content local. One that sends page content to a remote service for processing has copied it — which is fine for a recipe page and very much not fine for an inbox full of contracts. Our own position is simple and it is the standard we hold ourselves to: your data should stay in your browser unless you explicitly send it somewhere. That is the principle AI Memory Guard was built around, and it is the question to put to every AI tool you use.
Make it a habit, not a project
Put a quarterly reminder on the calendar to re-run the audit. Extensions update, permissions creep, and the tool you trusted last year is not automatically the tool you trusted. Ten minutes, four times a year, is the whole cost of keeping your browser clean.