Due to expired certificate, all Firefox extensions disabled

Update: a partial fix has been shipped by Mozilla A few hours ago a security certificate that Mozilla used to sign Firefox add-ons expired. What this means is that every add-on signed by that certificate, which seems to be nearly all of them, will now be automatically disabled by Firefox as security measure. In simpler terms, Firefox doesn't trust any add-ons right now. Basically, all your Firefox extensions will be disabled and won't work until Mozilla fixes this embarrassing issue. Until they do, you can go to about:config and set xpinstall.signature.required to false. This is obviously a major security issue, so only change this flag if you know what you're doing, and don't forget to set it back to true once Mozilla fixes the issue.