- The iptables mode of kube-proxy now tracks accepted packets that are destined for node-ports on localhost by introducing `kubeproxy_iptables_localhost_nodeports_accepted_packets_total` metric.

by this vulnerability if you run a Validating Admission Webhook for Nodes
that denies admission based at least partially on the old state of the
Node object.

**Note**: This only impacts validating admission plugins that rely on old
values in certain fields, and does not impact calls from kubelets that go
through the built-in NodeRestriction admission plugin.

**Affected Versions**:
  - kube-apiserver v1.20.0 - v1.20.5

objects identical to the saved originals. The format supports non-numerical state such as vocabulary files and lookup tables, and it is easy to customize in the case of custom layers with exotic elements of state (e.g. a FIFOQueue). The format does not rely on bytecode or pickling, and is safe by default. Note that as a result, Python `lambdas` are disallowed at loading time. If you want to use `lambdas`, you can pass `safe_mode=False` to the loading method (only do this if you trust the source of the...

http/2 requests from multiple clients share the same backend connection. An API server on a private network may choose not to enable the kube-apiserver mitigation to prevent performance regressions for unauthenticated clients. Authenticated requests rely on the fix in golang.org/x/net v0.17.0 alone. https://issue.k8s.io/121197 tracks further mitigation of http/2 attacks by authenticated clients. ([#121199](https://github.com/kubernetes/kubernetes/pull/121199), [@enj](https://github.com/enj)) [SIG API...

6))

* [Action required] The validation rule for metadata.initializers.pending[x].name is tightened. The initializer name must contain at least three segments, separated by dots. You can create objects with pending initializers and not rely on the API server to add pending initializers according to `initializerConfiguration`. If you do so, update the initializer name in the existing objects and the configuration files to comply with the new validation rule.([#51283](https://github.co...

* Default values differ between the Kubelet's componentconfig (config file) API and the Kubelet's command line. Be sure to review the default values when migrating to using a config file. For example, the authz mode is set to "AlwaysAllow" if you rely on the command line, but defaults to the more secure "Webhook" mode if you load config from a file. ([#59666](https://github.com/kubernetes/kubernetes/pull/59666), [@mtaufen](https://github.com/mtaufen))

- Kubeadm: when using a custom image repository for CoreDNS kubeadm now will append the "coredns"  image name instead of  "coredns/coredns", thus restoring the behaviour existing before the v1.21 release. Users who rely on nested folder for the coredns image should set the "clusterConfiguration.dns.imageRepository" value including the nested path name (e.g using "registry.company.xyz/coredns" will force kubeadm to use "registry.company.xyz/coredns/coredns" image)....

* The CustomResourceDefaulting feature is promoted to beta and enabled by default. Defaults may be specified in structural schemas via the `apiextensions.k8s.io/v1` API. See https://kuberne...

by this vulnerability if you run a Validating Admission Webhook for Nodes
that denies admission based at least partially on the old state of the
Node object.

**Note**: This only impacts validating admission plugins that rely on old
values in certain fields, and does not impact calls from kubelet that go
through the built-in NodeRestriction admission plugin.

**Affected Versions**:
  - kube-apiserver v1.20.0 - v1.20.5

http/2 requests from multiple clients share the same backend connection. An API server on a private network may choose not to enable the kube-apiserver mitigation to prevent performance regressions for unauthenticated clients. Authenticated requests rely on the fix in golang.org/x/net v0.17.0 alone. https://issue.k8s.io/121197 tracks further mitigation of http/2 attacks by authenticated clients. ([#121196](https://github.com/kubernetes/kubernetes/pull/121196), [@enj](https://github.com/enj)) [SIG API...