- Kube-apiserver: regular expressions specified with the `--cors-allowed-origins` option are now validated to match the entire `hostname` inside the `Origin` header of the request and 
  must contain '^' or the '//' prefix to anchor to the start, and '$' or the port separator ':' to anchor to 

* `kubectl run --env` no longer supports CSV parsing. To provide multiple env vars, use the `--env` flag multiple times instead of having env vars separated by commas. E.g. `--env ONE=1 --env TWO=2` instead of `--env ONE=1,TWO=2`. ([#47460](https://github.com/kubernetes/kubernetes/pull/47460), [@mengqiy](https://github.com/mengqiy))

- Added a new container based image for running e2e tests ([#69368](https://github.com/kubernetes/kubernetes/pull/69368), [@dims](https://github.com/dims))
- The `LC_ALL` and `LC_MESSAGES` env vars can now be used to set desired locale for `kubectl` while keeping `LANG` unchanged. ([#69500](https://github.com/kubernetes/kubernetes/pull/69500), [@m1kola](https://github.com/m1kola))

* Fixes in HPA: consider only running pods; proper denominator in avg request calculations. ([#33735](https://github.com/kubernetes/kubernetes/pull/33735), [@jszczepkowski](https://github.com/jszczepkowski))

* Return container command exit codes in kubectl run/exec ([#26541](https://github.com/kubernetes/kubernetes/pull/26541), [@sttts](https://github.com/sttts))
* Fix kubectl describe to display a container's resource limit env vars as node allocatable when the limits are not set ([#29849](https://github.com/kubernetes/kubernetes/pull/29849), [@aveshagarwal](https://github.com/aveshagarwal))

* Support KUBE_MAX_PD_VOLS on Azure ([#41398](https://github.com/kubernetes/kubernetes/pull/41398), [@codablock](https://github.com/codablock))

#### kubernetes Core Known Issues

- Kube Proxy crashes infrequently due to a docker bug ([#24000](https://github.com/docker/docker/issues/24000))
  - This issue can be resolved by restarting docker daemon
- CORS works only in insecure mode ([#24086](https://github.com/kubernetes/kubernetes/issues/24086))

      * Added exported env vars to kubectl plugins so that plugin developers have access to global flags, namespace, the plugin descriptor and the full path to the caller binary.

  * Enhancement