I can't recall if Microsoft has ever done this before but yesterday the company made the unusual decision to delay its Patch Tuesday. We're not sure what's going on as Microsoft isn't revealing a lot of details beyond a cryptic statement that they discovered a last minute issue that could impact some customers. The wording seems to suggest they may have discovered a significant enough bug that could impact a small number of users.
Our top priority is to provide the best possible experience for customers in maintaining and protecting their systems. This month, we discovered a last minute issue that could impact some customers and was not resolved in time for our planned updates today.
After considering all options, we made the decision to delay this month’s updates. We apologize for any inconvenience caused by this change to the existing plan.
It's unknown when Microsoft will roll out these security patches. Among other things, this month's Patch Tuesday cycle will fix a zero-day security flaw in Microsoft's SMB file sharing protocol that can crash computers when an attacker makes a connection.