Firefox disables all add-ons thanks to the One Pesky certificate

  • Firefox users may have noticed that some of their add-ons / extensions have suddenly stopped working today.
  • Under the extensions tab, Firefox shows “its use could not be verified in Firefox and it has been disabled”. According to the Mozilla bug tracker, this is actually an error and is explained as “all add-ons are disabled due to the expiration of the intermediate signing certificate”.
  • This problem occurred at 5 AM (local time) or 12 AM GMT / UTC, all thanks to the error mentioned above.
  • The affected extensions include LastPass, Ghostery, Download Manager (S3), Dark Mode, Honey, uBlock Origin, Greasemonkey, NoScript and others. The affected extensions have stopped working completely and can not be downloaded again from the store.

Temporary arrangement

Firefox disables all add-ons thanks to the One Pesky certificate

  1. Currently, the only solution to this problem is to find a replacement or simply delete the affected extensions. However, if you use the developer of Firefox or Nightly Build, there is a temporary solution. Look in about: config and set the value “xpinstall.signatures.required” to false. Some users have reported that this solution solves the problem temporarily.
  2. If you are in a different version of Firefox, you must enable additional debugging and you will have to manually upload the .xpi file of each extension each time you start the browser.
  3. Firefox is working to solve this problem. There is no ETA for a solution yet.