browser.webRequest.onBeforeRequest w/ blocking causes blocking indefinitely if host permissions are not specified

Confirmed Issue #9483012 • Assigned to Sanchit A.


Marcus P.
Oct 23, 2016
This issue is public.
Found in
  • Microsoft Edge
Found in build #
Reported by 2 people

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Steps to reproduce

Adding a browser.webRequest.onBeforeRequest handler that blocks causes any requests to block indefinitely, and can cause previously opened tabs to close as they try to refresh/reload.

  1. Load the extension files attached
  2. Navigate to any website, including websites other than Facebook

Notice that the site will never load. For Facebook, the desired behavior is that it won’t navigate at all (not pretend to be navigating indefinitely). For any other website, the desired behavior is no observable difference between the extension being on or off.


  1. Enable reopen closed tabs on startup
  2. Open some tabs (to any sites)
  3. Close and Reopen Edge
  4. Enable extension
  5. Click on non-focused tabs

They will be closed as they try to reload. The desired effect here is to cancel the navigation and remain on the cached page (or a blank page).


Comments and activity

  • Microsoft Edge Team

    Changed Assigned To to “Ibrahim O.”

    Changed Assigned To to “Sebastian P.”

    Changed Assigned To from “Sebastian P.” to “Sermet I.”

    Changed Assigned To from “Sermet I.” to “Scott L.”

    Changed Status to “Confirmed”

  • Thanks for filing this bug! It actually looks like there are two issues here. The first is the fact that navigating to a blocked resource will cause the tab to appear as if it is loading indefinitely rather than failing gracefully like Chrome does.

    The second is the fact that failing to specify host permissions in the extension manifest file will result in the behavior you’re noticing. If you include "://*" in the permissions section of the manifest, you should see the indefinite hang/closing existing tab behavior disappear. I’m going to use this bug to track the latter issue, and I’ll create a new issue for the lack of error messaging. Thanks again!  

  • Microsoft Edge Team

    Changed Title from “browser.webRequest.onBeforeRequest w/ blocking causes blocking indefinitely” to “browser.webRequest.onBeforeRequest w/ blocking causes blocking indefinitely if host permissions are not specified”

    Changed Assigned To from “Scott L.” to “Liang Z.”

    Changed Assigned To from “Liang Z.” to “Vasanth C.”

    Changed Status from “Confirmed”

    Changed Status to “Confirmed”

    Changed Assigned To from “Vasanth C.” to “Sanchit A.”

    Changed Assigned To from “Sanchit A.” to “Sebastian P.”

    Changed Assigned To from “Sebastian P.” to “Irfan A.”

    Changed Assigned To from “Irfan A.” to “Sanchit A.”

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