Mozilla releases browser version 66.0.4 in the stable channel. It proposes a fix for the broken certificate chain (or trust chain) that caused the browser extensions to be disabled, rendering them obsolete.
At issue for this concern, which mainly affected Firefox users over the weekend, was the expiration of an intermediate signature certificate. Firefox was then no longer able to check extensions.
The update concerns Firefox on the computer, as well as Firefox for Android and the ESR version of Firefox (Extended Support Release; version 60.6.2). In addition to the deactivation of web extensions, the omission of Mozilla had also had an impact on themes, search engines and language packs.
In response to the most pressing need, Mozilla had developed a hotfix that was distributed by the Studies system, which is closely linked to the telemetry data. However, the dissemination may have been lengthy or not satisfactory for all. Firefox Update 66.0.4 includes a new intermediate signature certificate that has not expired and forces a new signature verification.
Mozilla has arranged for the problem to be fixed by Monday to avoid a more noticeable impact for a week’s start. The Firefox 66.0.4 release notes indicate that some small frustrations persist.
For a small number of extensions, they may be listed as unsupported or not appear in about:addons. Data is not lost and users can reinstall extensions and recover data. For themes, reactivation may also be necessary.