You know the phrase “shooting yourself in the foot” -- wielding a tool or capability with great power that, if not used carefully, has great capacity to cause harm, to the wielder and others. A “footgun” is a (mis)feature of some system that makes it more likely that this will happen. You thought security was an intrinsic feature of the container concept? Well, it seems <https://www.theregister.com/2021/06/29/newsblur_docker_ransomware/> Docker has long had an oddly insecure default setting, where network ports on a container are automatically punched through your kernel’s firewall settings, allowing access from the entire Internet. This is often not what you want.