Is User-Agent Switcher safe?

Low risk

User-Agent Switcher writes the configured UA string to each page's localStorage, where any page script can read it.

The extension injects a content script into every page (matching *://*/*) that stores the active user-agent string under the key 'useragent-switcher-uastring' in the visited site's own localStorage. Any JavaScript running on that page can retrieve this value, revealing both that the extension is installed and which user-agent the user has configured. No data is transmitted to external servers; the exposure is local to each page origin.

Part of this rating comes from analysis signals we haven't published as detailed findings yet.

Linderv0.3.3Firefox Add-ons
17Risk
Who publishes it

Linder - no other listings under this identity

What this publisher told the store about itself, and the other listings that told it the same thing.

AI-generated. Findings may contain errors. Those marked Verified have been manually reviewed.

Publishers can request a review.

What it can do

Permissions this extension asks for, as declared in version 0.3.3. Asking for a permission is not a finding on its own - it is what the extension can do if it chooses to.

  • Read and change your data on every site you visit

    *://*/*

  • Store data in your browser

    storage

  • Run its own code inside the pages you visit

    scripting

  • Block and redirect the requests your browser makes

    declarativeNetRequest

Updated 2 November 2026amo-770970