- kube-apiserver: a new `--requestheader-uid-headers` flag allows configuring request header authentication to obtain the authenticating user's UID from the specified headers. The suggested value for the new option is `X-Remote-Uid`. When specified, the `kube-system/extension-apiserver-authentication` configmap will include the value in its `.data[requestheader-uid-headers]` field. ([#115834](https://github.com/kubernetes/kubernetes/pull/115834), [@s...

- Fixed an issue where the kubelet token cache returned stale tokens when service accounts were recreated with the same name. The cache is now UID-aware. Additionally, the new `TokenRequestServiceAccountUIDValidation` feature gate (Beta, enabled by default) ensures the `TokenRequest` UID matches the service account UID when set. ([#132803](https://github.com/kubernetes/kubernetes/pull/132803), [@aramase](https://github.com/aramase)) [SIG API Machinery, Auth, Node and Testing]

- Client-go impersonation config can specify a UID to pass impersonated uid information through in requests. ([#104483](https://github.com/kubernetes/kubernetes/pull/104483), [@margocrawf](https://github.com/margocrawf))

* Updating apiserver to return UID of the deleted resource. Clients can use this UID to verify that the resource was deleted or waiting for finalizers. ([#45600](https://github.com/kubernetes/kubernetes/pull/45600), [@nikhiljindal](https://github.com/nikhiljindal))

- Kubernetes components that accepted X.509 client certificate authentication now read the user UID from a certificate subject name RDN with object ID `1.3.6.1.4.1.57683.2`. An RDN with this object ID had to contain a string value and appear no more than once in the certificate subject. Reading the user UID from this RDN could be disabled by setting the beta feature gate `AllowParsingUserUIDFromCertAuth` to `false`(until the feature gate graduated to...

  - `alpha` support (guarded by the `ServiceAccountTokenPodNodeInfo` feature gate) for including the node name (and uid, if the node exists) as additional claims in service account tokens it issues which are bound to pods, and `authentication.kubernetes.io/node-name` and `authentication.kubernetes.io/node-uid` extra user info when the token is used to authenticate.

- Pods owned by a Job now uses the labels `batch.kubernetes.io/job-name` and `batch.kubernetes.io/controller-uid`.
  The legacy labels `job-name` and `controller-uid` are still added for compatibility. ([#114930](https://github.com/kubernetes/kubernetes/pull/114930), [@kannon92](https://github.com/kannon92))

  - `response.patch` and `response.patchType` are not permitted from validating admission webhooks
  - `apiVersion: "admission.k8s.io/v1"` is required
  - `kind: "AdmissionReview"` is required
  - `response.uid: "<value of request.uid>"` is required
  - `response.patchType: "JSONPatch"` is required (if `response.patch` is set) ([#80231](https://github.com/kubernetes/kubernetes/pull/80231), [@liggitt](https://github.com/liggitt))

* The options passed to a flexvolume plugin's mount command now contains the pod name (`kubernetes.io/pod.name`), namespace (`kubernetes.io/pod.namespace`), uid (`kubernetes.io/pod.uid`), and service account name (`kubernetes.io/serviceAccount.name`). ([#39488](https://github.com/kubernetes/kubernetes/pull/39488), [@liggitt](https://github.com/liggitt))

  - A namespaced object with an ownerReference referencing a uid of a namespaced kind which does not exist in the same namespace is now consistently treated as though that owner does not exist, and the child object is deleted.