Kubernetes makes it easier to manage a container environment by organizing application containers into pods, nodes (physical or virtual machines) and clusters. Multiple nodes form a cluster, managed by a master that coordinates cluster-related activities like scaling, scheduling, or updating apps. Each node has an agent called Kubelet that facilitates communication with the Kubernetes master via the API. The number of nodes available in a Kubernetes system can be hundreds and even thousands.
The security bug was discovered by Darren Shepherd, co-founder of Rancher Labs company that provides Kubernetes-as-a-Service solution Rancher. Now tracked as CVE-2018-1002105, the flaw is critical, with a Common Vulnerability Scoring System (CVSS) score of 9.8 out of 10. The problem has been addressed in the latest Kubernetes revisions: v1.10.11, v1.11.5, v1.12.3, and v1.13.0-rc.1. Kubernetes releases prior to these along with the products and services based on them are affected by CVE-2018-1002105.