Are containers less secure than VMs in practice?

Virtualization by containers is often regarded as less secure than VMs, because the latter ensures an higher degree of isolation as the guests have their own OS rather than interacting directly with a shared kernel in the host. While this makes sense in theory and many authors repeat it like a mantra, they seldom provide practical evidence to support such claim. Do you know any good examples of past vulnerabilities affecting containers (e.g. Docker, LXC, ...) that would strike a …

containers cybersecurity vms