The Kubernetes API server mistakenly allows access to a cluster-scoped custom resource if the request is made as if the resource were namespaced. Authorizations for the resource accessed in this manner are enforced using roles and role bindings within the namespace, meaning that a user with access only to a resource in one namespace could create, view update or delete the cluster-scoped resource (according to their namespace role privileges).

A flaw was found kubernetes. The parsing of YAML manifests by the Kubernetes API server could lead to a denial-of-service attack leaving it vulnerable to an instance of a "billion laughs" attack. The highest threat from this vulnerability is to system availability.

The kubectl cp command allows copying files between containers and the user machine. To copy files from a container, Kubernetes runs tar inside the container to create a tar archive, copies it over the network, and kubectl unpacks it on the user’s machine. If the tar binary in the container is malicious, it could run any code and output unexpected, malicious results. An attacker could use this to write files to any path on the user’s machine when kubectl cp is called, limited only by the system permissions of the local user. Kubernetes affected versions include versions prior to 1.12.9, versions prior to 1.13.6, versions prior to 1.14.2, and versions 1.1, 1.2, 1.4, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 1.10, 1.11.