Chrome Extension Reading All Sites Permission Explained

Chrome extension reading all sites permission

Short answer

When a Chrome extension can read all sites, it usually has <all_urls> host access and a content script or scripting permission. That allows code to run on nearly every page you visit and potentially read page content. It does not necessarily mean the extension reads or sends everything.

Drop an extension package hereor choose a file from your deviceChoose a fileSupported: CRX, XPI, ZIP, manifest.json. Maximum size: 25 MB.

Processed locallyCode is never executed

Your file stays in this browser. Parsing happens in a Web Worker; the extension code is read, never executed.

What the scan checks

Permissions, host access, content scripts, background scripts, CSP, externally_connectable, web-accessible resources, JavaScript patterns, referenced domains and risk categories.

MV3MV2CRXXPIZIPJSON

Static analysis shows references and patterns. It cannot prove that network activity happened or that an extension is malicious.

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See permission, domain and finding changes between two packages.

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How all-site reading works

Host access alone lets extension APIs query matching URLs. Reading and changing page content requires injection, often through content scripts declared in the manifest or the scripting API.

The extension can then access the page DOM, observe input and read cookies that are not HttpOnly. It can also combine page context with tab, history or storage data depending on other permissions.

Why legitimate extensions need it

Password managers, ad blockers, translation tools, accessibility helpers and developer utilities often need broad access to recognize or modify pages across sites. The access can be justified even though the privacy impact is large.

The key questions are whether the feature truly needs every site, whether the publisher explains data handling and whether the extension sends page content to external hosts.

Limiting exposure

Use the browser's site-access control to restrict an installed extension where possible. Remove extensions that are no longer needed. Prefer alternatives that name the sites they need.

If you must use a broad extension for sensitive accounts, consider a separate browser profile with a smaller extension set.

Frequently asked questions

Does all-site permission mean the extension sees my passwords?

It may be able to read form fields on pages where its scripts run. Whether it captures them is a separate question that static analysis cannot answer conclusively.

Can I revoke all-site access?

Many Chromium browsers allow you to restrict site access per extension. Check the extension details page; some extensions may stop working.

Why does a coupon extension ask for all sites?

It may check many retail sites for discounts. That is a common but broad design choice. Review the publisher and domains before trusting it.

Last reviewed: October 31, 2026