Ask HN: Move fast and break things – what happens to security and integrity?

I've been binging engineering blogs of companies like Facebook and Instagram recently. One of their core philosophies is moving fast - using continuous delivery to deploy things really quickly in production.

However, one of my big fear when releasing and updating code is maintaining security of the system and integrity of the data, which means that releases need to be done carefully.

Is security and integrity less important than time to market / speed of deployment? Or are there plenty of mechanisms that try to catch and prevent this. If so, what are they?