Filter list downloads fail due to CORS error

Environment

  • Reported by TheSarcasticWit (see forum post):
    • Chrome 81.0.4044.129 (Official Build) (64-bit)
    • No browser flags set.
    • Other installed extensions:
      • Awesome Reload Tabs Button
      • Camelizer
      • Honey
      • LastPass
      • Microsoft Rewards
      • MyPoints
      • Print Friendly
      • RetailMeNot
  • Reported by shahaashit (see forum post):
    • macOS Catalina v10.15.3
    • Chrome 83.0.4103.116 (Official Build) (64-bit)
    • Adblock Plus 3.8.4 (even after reinstalling)
  • Reported by Delenn (see forum post):
    • Chrome 86.0.4240.75
    • Adblock Plus 3.9.5

How to reproduce

TBD

Observed behavior

Filter list downloads fail with the following errors:

Errors reported by TheSarcasticWit 
Access to fetch at 'https://easylist-downloads.adblockplus.org/abp-filters-anti-cv.txt?addonName=adblockpluschrome&addonVersion=3.8.4&application=chrome&applicationVersion=81.0.4044.122&platform=chromium&platformVersion=81.0.4044.122&lastVersion=202004282150&downloadCount=4%2B&firstVersion=20200428' from origin 'chrome-extension://cfhdojbkjhnklbpkdaibdccddilifddb' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.
easylist-downloads.adblockplus.org/abp-filters-anti-cv.txt?addonName=adblockpluschrome&addonVersion=3.8.4&application=chrome&applicationVersion=81.0.4044.122&platform=chromium&platformVersion=81.0.4044.122&lastVersion=202004282150&downloadCount=4%2B&firstVersion=20200428:1 Failed to load resource: net::ERR_FAILED
  Adblock Plus: Downloading URL https://easylist-downloads.adblockplus.org/abp-filters-anti-cv.txt failed (synchronize_connection_error)
  Download address: https://easylist-downloads.adblockplus.org/abp-filters-anti-cv.txt?addonName=adblockpluschrome&addonVersion=3.8.4&application=chrome&applicationVersion=81.0.4044.122&platform=chromium&platformVersion=81.0.4044.122&lastVersion=202004282150&downloadCount=4%2B&firstVersion=20200428
  Server response: 0

Access to fetch at 'https://easylist-downloads.adblockplus.org/abp-filters-anti-cv.txt?addonName=adblockpluschrome&addonVersion=3.8.4&application=chrome&applicationVersion=81.0.4044.122&platform=chromium&platformVersion=81.0.4044.122&lastVersion=202004282150&downloadCount=4%2B&firstVersion=20200428' from origin 'chrome-extension://cfhdojbkjhnklbpkdaibdccddilifddb' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.
easylist-downloads.adblockplus.org/abp-filters-anti-cv.txt?addonName=adblockpluschrome&addonVersion=3.8.4&application=chrome&applicationVersion=81.0.4044.122&platform=chromium&platformVersion=81.0.4044.122&lastVersion=202004282150&downloadCount=4%2B&firstVersion=20200428:1 Failed to load resource: net::ERR_FAILED
Adblock Plus: Downloading URL https://easylist-downloads.adblockplus.org/abp-filters-anti-cv.txt failed (synchronize_connection_error)
Download address: https://easylist-downloads.adblockplus.org/abp-filters-anti-cv.txt?addonName=adblockpluschrome&addonVersion=3.8.4&application=chrome&applicationVersion=81.0.4044.122&platform=chromium&platformVersion=81.0.4044.122&lastVersion=202004282150&downloadCount=4%2B&firstVersion=20200428
Server response: 0


Access to fetch at 'https://easylist-downloads.adblockplus.org/fanboy-social.txt?addonName=adblockpluschrome&addonVersion=3.8.4&application=chrome&applicationVersion=81.0.4044.122&platform=chromium&platformVersion=81.0.4044.122&lastVersion=0&downloadCount=0&firstVersion=20200428' from origin 'chrome-extension://cfhdojbkjhnklbpkdaibdccddilifddb' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.
easylist-downloads.adblockplus.org/fanboy-social.txt?addonName=adblockpluschrome&addonVersion=3.8.4&application=chrome&applicationVersion=81.0.4044.122&platform=chromium&platformVersion=81.0.4044.122&lastVersion=0&downloadCount=0&firstVersion=20200428:1 Failed to load resource: net::ERR_FAILED
Adblock Plus: Downloading URL https://easylist-downloads.adblockplus.org/fanboy-social.txt failed (synchronize_connection_error)
Download address: https://easylist-downloads.adblockplus.org/fanboy-social.txt?addonName=adblockpluschrome&addonVersion=3.8.4&application=chrome&applicationVersion=81.0.4044.122&platform=chromium&platformVersion=81.0.4044.122&lastVersion=0&downloadCount=0&firstVersion=20200428
Server response: 0
Errors reported by shahaashit 
Access to fetch at 'https://easylist-downloads.adblockplus.org/easylist.txt?addonName=adblockpluschrome&addonVersion=3.8.4&application=chrome&applicationVersion=83.0.4103.116&platform=chromium&platformVersion=83.0.4103.116&lastVersion=202006260831&downloadCount=1&firstVersion=20200626' from origin 'chrome-extension://cfhdojbkjhnklbpkdaibdccddilifddb' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.

adblockplus.js:7657 Adblock Plus: Downloading URL https://easylist-downloads.adblockplus.org/easylist.txt failed (synchronize_connection_error)
Download address: https://easylist-downloads.adblockplus. ... n=20200626
Server response: 0

Expected behavior

Filter list downloads succeed.

Edited by Thomas Greiner