CVE-2023-22651: Rancher Webhook is misconfigured during upgrade process

A failure in the update logic of Rancher’s admission Webhook may lead to the misconfiguration of the Webhook. This component enforces validation rules and security checks before resources are admitted into the Kubernetes cluster.

When the Webhook is operating in a degraded state, it no longer validates any resources, which may result in severe privilege escalations and data corruption.

The issue only affects users that upgrade from 2.6.x or 2.7.x to 2.7.2. Users that did a fresh install of 2.7.2 (and did not follow an upgrade path) are not affected.

The command below can be executed on the local cluster to determine whether the cluster is affected by this issue:

$ kubectl get validatingwebhookconfigurations.admissionregistration.k8s.io rancher.cattle.io

NAME                WEBHOOKS   AGE
rancher.cattle.io   0         19h

If the resulting webhook quantity is 0, the Rancher instance is affected.