There were two updates to Firefox this week 67.0.3 and lastly 67.0.4 to address two zero-day vulnerabilities that have been attacked in the wild and can compromise your system just by browsing to a malicious site.
Very unusual circumstances for Firefox -- usually quite stable. However, do use Help, About Firefox to get the latest (67.0.4) update to make your system immune to the two vulnerabilities.
Also, the Firefox Developer Edition browser had updates too.. latest version is 68.0b12 (64-bit)
