Libre software is more like plans to build a gas stove, and security bugs are more like it not having a safety such that malicious visitors can turn on an unlit stove to fill your house with gas.

Also lets be very clear here - software bugs aren't really capable of causing damage by themselves. If I set up a lone machine running a decades old Swiss cheese Linux distribution on a publicly accessible IP, the absolute worst that can happen is its bandwidth being used to create denials of service. It's those who create real-world reliance on inadequate software systems that deserve most of the blame for damages.