Your Firefox extensions are all disabled? That's a bug!

Many Firefox users around the world are browsing without their usual set of extensions after they suddenly stopped working earlier this evening. The event occurred as the clock rolled over on UTC (Coordinated Universal Time, aka GMT or Greenwich Mean Time), and impacted users quickly narrowed it down to "expiration of intermediate signing cert" -- as it's described on Mozilla's bug tracker.

Some Firefox users started to notice that installed browser extensions were all disabled in the web browser suddenly. Extensions would display "could not be verified for use in Firefox and has been disabled" messages in the add-ons manager of the browser. Firefox would display "One or more installed add-ons cannot be verified and have been disabled" at the top as a notification next to that.

Affected extensions include LastPass, Ghostery, Download Manager (S3), Dark Mode, Honey, uBlock Origin, Greasemonkey, NoScript, and others.

Update: Mozilla started to roll out a fix for Release, Beta, and Nightly versions of Firefox. The fix uses Mozilla Studies, and you need to make sure that this is enabled to get it. Mozilla notes that you may disable Studies again after the fix is applied and add-ons have been re-enabled. You need to make sure that "Allow Firefox to install and run studies" is checked on about references#privacy.

Your Firefox extensions are all disabled? Thats a bug! - gHacks Tech News

Firefox disabled all add-ons because a certificate expired (updated)

Update 3 (5/4, 7:30 AM ET): The team has announced a hotfix is rolling out now. It's applied in the background, so you shouldn't have to do anything to receive it. However, to make sure you get it right away, you can follow these instructions:

In order to be able to provide this fix on short notice, we are using the Studies system. You can check if you have studies enabled by going to Firefox Preferences -> Privacy & Security -> Allow Firefox to install and run studies.

You can disable studies again after your add-ons have been re-enabled.

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We rolled out a hotfix that re-enables affected add-ons. The fix will be automatically applied in the background within the next few hours.
For more details, please check out the update at Certificate issue causing add-ons to be disabled or fail to install

— Mozilla Add-ons (@mozamo) May 4, 2019
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So sorry for the issue we're having with add-ons right now!

We're working hard to fix it and will keep you updated.

— Firefox (@firefox) May 4, 2019
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No ETA for the fix yet; we're waiting on test results before making decision.

— Mozilla Add-ons (@mozamo) May 4, 2019
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Temporary workaround posted here if you can't wait for the fix:

As of 12:00 am UTC, nearly all Firefox extensions are disabled. Itt work. : firefox