- Added warnings to the Services API. Kubernetes now warns for Services in the case of:
  - IPv4 addresses with leading zeros
  - IPv6 address in non-canonical format (RFC 5952) ([#114505](https://github.com/kubernetes/kubernetes/pull/114505), [@aojea](https://github.com/aojea))

- Removed leading zeros from the etcd member ID in kubeadm log messages. ([#117919](https://github.com/kubernetes/kubernetes/pull/117919), [@dlipovetsky](https://github.com/dlipovetsky)) [SIG Cluster Lifecycle]

- `VolumeBindingArgs` now allow `BindTimeoutSeconds` to be set as zero, while the value zero indicates no waiting for the checking of volume binding operation. ([#99835](https://github.com/kubernetes/kubernetes/pull/99835), [@chendave](https://github.com/chendave)) [SIG Scheduling and Storage]

* Change CollisionCount from int64 to int32 across controllers ([#50575](https://github.com/kubernetes/kubernetes/pull/50575), [@dixudx](https://github.com/dixudx))
* fix GPU resource validation that incorrectly allows zero limits ([#50218](https://github.com/kubernetes/kubernetes/pull/50218), [@dixudx](https://github.com/dixudx))

- Since golang 1.17 both net.ParseIP and net.ParseCIDR rejects leading zeros in the dot-decimal notation of IPv4 addresses,
  Kubernetes will keep allowing leading zeros on IPv4 address to not break the compatibility.
  IMPORTANT: Kubernetes interprets leading zeros on IPv4 addresses as decimal, users must not rely on parser alignment to not being impacted by the associated security advisory:

- Added an e2e test to verify that the cluster is not vulnerable to CVE-2021-29923 when using Services with IPs with leading zeros, note that this test is a necessary but not sufficient condition, all the components in the clusters that consume IPs addresses from the APIs MUST interpret them as decimal or discard them. ([#107552](https://github.com/kubernetes/kubernetes/pull/107552),...

`apiserver_kube_aggregator_x509_missing_san_total` and `apiserver_webhooks_x509_missing_san_total`. This metric measures a number of connections to webhooks/aggregated API servers that use certificates without Subject Alternative Names. It being non-zero is a warning sign that these connections will stop functioning in the future since Golang is going to deprecate x509 certificate subject Common Names for server hostname verification. ([#95396](https://github.com/kubernetes/kubernetes/pull/95396),...

- In the PriorityLevelConfiguration object, the `nominalConcurrencyShares` field now accepts a zero value in both the `flowcontrol.apiserver.k8s.io/v1` and `flowcontrol.apiserver.k8s.io/v1beta3` APIs.
   ([#123001](https://github.com/kubernetes/kubernetes/pull/123001), [@tkashem](https://github.com/tkashem))

- Fixed CEL estimated cost of `replace()` to handle a zero length replacement string correctly.
  Previously this would cause the estimated cost to be higher than it should be. ([#120097](https://github.com/kubernetes/kubernetes/pull/120097), [@jpbetz](https://github.com/jpbetz)) [SIG API Machinery]

- Fixed relative CPU priority for pods where containers explicitly request zero cpu by giving the lowest priority instead of falling back to the cpu limit to avoid possible cpu starvation of other pods. ([#108832](https://github.com/kubernetes/kubernetes/pull/108832), [@waynepeking348](https://github.com/waynepeking348))