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Browser MCP - Automate your browser using VS Code, Cursor, Claude, and more

Version 1.3.4 View in Chrome Web Store

Last scanned: about 17 hours ago

Extension Details

Developer: browsermcp.io

Rating: 4.8 ★ (652 ratings)

Users: 100,000

Context-Aware Verdict

CRITICAL

Overall Risk

Trust Factors:

The extension has a strong user base with 100,000 users and an excellent 4.8-star rating from 652 reviews, suggesting legitimate functionality. The developer domain browsermcp.io appears to be purpose-built for this tool, and the description clearly states its automation capabilities for browser control via development tools like VS Code and Claude.

Concerns:

The extension requests an extremely powerful combination of permissions that essentially grants complete browser control. The debugger permission is particularly concerning as it can manipulate other extensions and browser internals. Combined with broad host permissions and content script injection across all websites, this creates a perfect storm for potential abuse. The webNavigation and tabs permissions enable comprehensive browsing surveillance. While these permissions align with the stated automation functionality, they represent maximum possible access to user data and browser activity.

Recommendations:

Given the critical risk level, run this extension in a completely isolated Chrome profile dedicated solely to development work. Never use this profile for personal browsing, banking, or accessing sensitive accounts. Only install when actively using the automation features, and consider disabling it when not needed. Ensure you fully trust the developer and understand that this extension has unprecedented access to your entire browsing session. Monitor for any unexpected behavior and regularly review what data the extension might be collecting.

Findings

HIGH

Broad Content Script Injection

This extension can inject scripts into any website. This means it could potentially read sensitive data, modify website content, or steal credentials.

HIGH

Broad Host Permissions

This extension has broad host permissions allowing it to access many or all websites. This could potentially be used to steal sensitive data or track browsing activity.

HIGH

High-Risk Permission: debugger

This extension has the debugger permission. Can debug and manipulate other extensions/apps. This could potentially be used maliciously to compromise security or privacy.

HIGH

High-Risk Permission: tabs

This extension has the tabs permission. Can access browser tab information and manipulate tabs. This could potentially be used maliciously to compromise security or privacy.

HIGH

High-Risk Permission: webNavigation

This extension has the webNavigation permission. Can track your web navigation. This could potentially be used maliciously to compromise security or privacy.

MEDIUM

Medium-Risk Permission: storage

This extension has the storage permission. Can store data locally.

Security Analysis Details

Required Permissions:

debugger
scripting
storage
tabs
webNavigation

Host Permissions:

<all_urls>

Embedded URLs (43 total):

https://github.com/wxt-dev/wxt/issues/371	https://wxt.dev/guide/go-further/testing.html
https://developer.chrome.com/docs/extensions/reference/manifest/key	https://developer.chrome.com/docs/extensions/reference/manifest/externally_connectable
https://api2.amplitude.com/2/httpapi	https://api.eu.amplitude.com/2/httpapi
https://api2.amplitude.com/batch	https://api.eu.amplitude.com/batch
https://www.docs.developers.amplitude.com/data/sdks/browser-2/#tracking-default-events	https://sr-client-cfg.amplitude.com/config
https://sr-client-cfg.stag2.amplitude.com/config	https://sr-client-cfg.eu.amplitude.com/config
https://app.amplitude.com	https://app.eu.amplitude.com
https://apps.stag2.amplitude.com	https://github.com/uuidjs/uuid#getrandomvalues-not-supported
https://app.posthog.com/home#panel=support%3Asupport%3A.	https://sentry.io/organizations/
https://posthog.com/docs/billing/limits-alerts	http://www.w3.org/2000/svg
http://yandex.com/bots	https://app.posthog.com
https://us.i.posthog.com	https://us.posthog.com
http://www.example.com	https://docs.sentry.io/platforms/javascript/best-practices/browser-extensions/
https://sentry.io/welcome/	https://spotlightjs.com/sidecar/npx/
https://o447951.ingest.sentry.io/api/1337/envelope/?sentry_version=7&sentry_key=1337&sentry_client=sentry.javascript.browser%2F1.33.7	https://app.browsermcp.io
https://github.com/mholt/PapaParse	https://clients2.google.com/service/update2/crx
https://tailwindcss.com	https://react.dev/errors/
http://www.w3.org/1998/Math/MathML	http://www.w3.org/1999/xlink
http://www.w3.org/XML/1998/namespace	https://reactrouter.com/en/main/routers/picking-a-router.
https://browsermcp.io	https://docs.browsermcp.io
https://sizzlejs.com/	https://js.foundation/
https://html.spec.whatwg.org/multipage/custom-elements.html#valid-custom-element-name

Raw Manifest

{
  "key": "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAtnIVuyyr0emD2C79jB4F6dzNaurwhd5cJdGhJFhNkQ9YcSBMfKHQAivecCE7KuOImGJ9D7hPZYE2DzDR5j0NWlGn7K/xNZer0t3d+AHJojWUgOMLYTXdn86WxjigdHIw3Bwbo9ElH0Z9pdNOrRy2SdXtCiq6iqTHUrXwxNdVnEKkAWPNyr5QcqmfJlq6iPuB36GUwo40XgKwVPxC9eChVWoK4U6XgNEkQf44oQRTxJkbvG7AYsU7LGaVdXXJwyKuwBhaQh5oHtAjjpujF9Sgwbd8IJSPBeF5ssRZAbCzr16yLV66D05/1RodJSia7E5OafCx78C/rLJ0tZyaOV+40wIDAQAB",
  "name": "Browser MCP - Automate your browser using VS Code, Cursor, Claude, and more",
  "icons": {
    "16": "icon/16.png",
    "32": "icon/32.png",
    "48": "icon/48.png",
    "128": "icon/128.png"
  },
  "action": {
    "default_icon": "/icon/48.png",
    "default_popup": "popup.html",
    "default_title": "Browser MCP"
  },
  "version": "1.3.4",
  "commands": {
    "_execute_action": {
      "suggested_key": {
        "default": "Alt+J"
      }
    }
  },
  "background": {
    "service_worker": "background.js"
  },
  "update_url": "https://clients2.google.com/service/update2/crx",
  "permissions": [
    "debugger",
    "scripting",
    "storage",
    "tabs",
    "webNavigation"
  ],
  "default_locale": "en",
  "content_scripts": [
    {
      "js": [
        "content-scripts/content.js"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "manifest_version": 3,
  "externally_connectable": {
    "matches": [
      "https://*.browsermcp.io/*"
    ]
  },
  "web_accessible_resources": [
    {
      "matches": [
        "<all_urls>"
      ],
      "resources": [
        "content-scripts/content.css"
      ]
    }
  ]
}

by ✦ Astarte

Browser MCP - Automate your browser using VS Code, Cursor, Claude, and more

Extension Details

Context-Aware Verdict

Findings

Security Analysis Details

Required Permissions:

Host Permissions:

Embedded URLs (43 total):

Raw Manifest

Detections

Manifest Findings