UBUNTU-CVE-2020-8561

A security issue was discovered in Kubernetes where actors that control the responses of MutatingWebhookConfiguration or ValidatingWebhookConfiguration requests are able to redirect kube-apiserver requests to private networks of the apiserver. If that user can view kube-apiserver logs when the lo...

CVE-2021-25735

A security issue was discovered in kube-apiserver that could allow node updates to bypass a Validating Admission Webhook. Clusters are only affected by this vulnerability if they run a Validating Admission Webhook for Nodes that denies admission based at least partially on the old state of the No...

Kubernetes: API Server DoS (crash?) if many large resources (~1MB each) are concurrently/repeatedly sent to an external Validating WebHook endpoint

Report Submission Form Summary: I was trying to explore a way to stealthily send lots of data outside a private GKE cluster by way of misusing the Validating Webhook mechanism. The idea would be that a cluster-admin could install a webhook and then initiate resources like a secret or configmap th...