Massive disruption is coming to websites that use digital certificates issued by Symantec or the brands that it has owned - Verisign, Thawte GeoTrust, and RapidSSL. One third or more of the net’s SSL certificates could be affected.
Effective this week, both the Chrome and Firefox browsers will not accept any SSL certificates issued by Symantec that were issued before June 2016. Symantec certificates that were issued after that date will not be accepted by both browsers starting in September 2018.
These drastic measures have been in the making for about a year. In March 2017 Google announced that it had lost all confidence in certificates issued by Symantec.
What had gone wrong? In short, the way how Symantec was issuing the certificates. Its issuance methods could allow untrusted third parties to issue certificates on Symantec’s behalf - without oversight. The rules that Symantec ignored had been decided by the industry standards group, the CA/B Forum, for certificates used