kube-apiserver authentication bypass vulnerability

An authentication bypass vulnerability was discovered in kube-apiserver. This issue could allow a remote, authenticated attacker who has been given permissions "update, patch" the "pods/ephemeralcontainers" subresource beyond what the default is. They would then need to create a new pod or patch one that they already have access to. This might allow evasion of SCC admission restrictions, thereby gaining control of a privileged pod.