For more information, see [#57198](https://github.com/kubernetes/kubernetes/issues/57198).

*   Mutating and validating webhook configurations are continuously polled by the API server (once per second). This issue will be fixed in a future release.

  For more information, see [#56357](https://github.com/kubernetes/kubernetes/issues/56357).

* apiserver: fixes handling and logging of panics in REST handlers to prevent crashes ([#71076](https://github.com/kubernetes/kubernetes/pull/71076), [@liggitt](https://github.com/liggitt))
* Fixes ability for admin/edit/view users to see controller revisions, needed for kubectl rollout commands ([#70699](https://github.com/kubernetes/kubernetes/pull/70699), [@liggitt](https://github.com/liggitt))

  2. If you were previously overriding the kube-proxy configuration for performance reasons, this may no longer be necessary. See https://kubernetes.io/docs/reference/networking/virtual-ips/#optimizing-iptables-mode-performance. ([#115138](https://github.com/kubernetes/kubernetes/pull/115138), [@danwinship](https://github.com/danwinship))

- Kubeadm: when using...

For initial installations, see the [Setup topics][] in the Kubernetes
documentation.

To upgrade to this release from a previous version, take any actions required
[Before Upgrading](#before-upgrading).

For more information about the release and for the latest documentation,
see the [Kubernetes documentation](https://kubernetes.io/docs/home/).

- In the API Priority and Fairness feature, priority levels that are exempt from limitation can now be given a nominal and a lendable concurrency and their dispatching borrows from the concurrency limits of the other priority levels.  For details see https://github.com/kubernetes/enhancements/tree/master/keps/sig-api-machinery/1040-priority-and-fairness#dispatching . ([#118782](https://github.com/kubernetes/kubernetes/pull/118782), [@MikeSpreitzer](https://github.com/MikeSpreitzer)) [SIG API Machinery]...

* fix detach azure disk issue due to dirty cache ([#71495](https://github.com/kubernetes/kubernetes/pull/71495), [@andyzhangx](https://github.com/andyzhangx))
* Fixes ability for admin/edit/view users to see controller revisions, needed for kubectl rollout commands ([#70699](https://github.com/kubernetes/kubernetes/pull/70699), [@liggitt](https://github.com/liggitt))

## Changelog since v1.17.8

## Urgent Upgrade Notes

### (No, really, you MUST read this before you upgrade)

 - CVE-2020-8559 (Medium): Privilege escalation from compromised node to cluster. See https://github.com/kubernetes/kubernetes/issues/92914 for more details.

## Changelog since v1.18.5

## Urgent Upgrade Notes

### (No, really, you MUST read this before you upgrade)

 - CVE-2020-8559 (Medium): Privilege escalation from compromised node to cluster. See https://github.com/kubernetes/kubernetes/issues/92914 for more details.

* Fixes ability for admin/edit/view users to see controller revisions, needed for kubectl rollout commands ([#70699](https://github.com/kubernetes/kubernetes/pull/70699), [@liggitt](https://github.com/liggitt))