Why containers are less secure that virtual machines?

Containers share the host operating system's kernel, meaning a vulnerability or misconfiguration in that shared kernel can be exploited by any container, potentially affecting all other containers and the host itself. This shared kernel constitutes a larger, single point of failure and attack surface at the host OS level compared to virtual machines, which each run their own isolated kernel.

While containers can consume excessive disk space leading to denial of service, this is a resource management issue rather than a fundamental security vulnerability related to the isolation model itself, which is the primary concern when comparing container and VM security.

A compromised container causing CPU starvation is a resource exhaustion issue, which can lead to denial of service, but it's not the primary architectural reason why containers offer weaker isolation and are considered less secure than virtual machines.

Containers being attached to the same virtual network is a network configuration choice; virtual machines can also be configured with shared virtual networks, so this is not a unique or fundamental reason for containers being less secure than VMs.