Browser permissions are the settings that control which websites, pages, tabs, clipboard data, or browser features an extension can read, change, or observe. In practice, they define how much visibility an add-on has into your browsing session. A permission to “read and change data on all sites” is far more powerful than access to a single trusted domain.
These permissions matter because many attacks abuse them instead of breaking into the target service itself. A malicious extension with broad access can capture chat prompts, copied text, page contents, and session details from web apps, including AI tools. Defenders should apply least privilege, review requested permissions before installation, remove unnecessary extensions, and use separate browser profiles for sensitive work. Good permission hygiene turns the browser from a data leak path into a controlled environment.