- When updating a CRD, per-expression cost limit check are now skipped for `x-kubernetes-validations` rules of versions that are not mutated. ([#121460](https://github.com/kubernetes/kubernetes/pull/121460), [@jiahuif](https://github.com/jiahuif))
- `CSINodeExpandSecret` feature has been promoted to `GA` in this release and is enabled

        * At Metadata audit level or higher, an annotation with key "mutation.webhook.admission.k8s.io/round_{round idx}_index_{order idx}" gets logged with JSON payload indicating a webhook gets invoked for given request and whether it mutated the object or not.

certificates directory as `kubelet-client.key` and `kubelet-client.crt`.  Subsequent certificates created by cert rotation were created in a combined PEM file that was atomically rotated as `kubelet-client-DATE.pem` in that directory, which meant clients relying on the `node.kubeconfig` generated by bootstrapping would never use a rotated cert.  The initial bootstrap certificate is now generated into the cert directory as a PEM file and symlinked to `kubelet-client-current.pem` so that the generated kubeconfig...

There is no mitigation from this issue.  Cluster admins should take care to secure aggregated API servers and should not grant access to mutate `APIService`s to untrusted parties.

**Affected Versions**:
  - kube-apiserver v1.25.0
  - kube-apiserver v1.24.0 - v1.24.4
  - kube-apiserver v1.23.0 - v1.23.10
  - kube-apiserver v1.22.0 - v1.22.14

    - `rest_client_certificate_rotation_age` a histogram reporting the age of a just rotated client certificate in seconds. ([#84382](https://github.com/kubernetes/kubernetes/pull/84382), [@sambdavidson](https://github.com/sambdavidson)) [SIG API Machinery, Auth, Cluster Lifecycle and Instrumentation]

## Changelog since v1.8.11

### Other notable changes

* GCE: Fix for internal load balancer management resulting in backend services with outdated instance group links. ([#62887](https://github.com/kubernetes/kubernetes/pull/62887), [@nicksardo](https://github.com/nicksardo))

* GCE: Fix for internal load balancer management resulting in backend services with outdated instance group links. ([#62887](https://github.com/kubernetes/kubernetes/pull/62887), [@nicksardo](https://github.com/nicksardo))

- The metric `apiserver_flowcontrol_request_concurrency_limit` has been deprecated and will be removed in a future release.  It is a duplicate of `apiserver_flowcontrol_nominal_limit_seats` (introduced in release 1.26) but has an outdated name and had an outdated HELP string. ([#118959](https://github.com/kubernetes/kubernetes/pull/118959), [@MikeSpreitzer](https://github.com/MikeSpreitzer)) [SIG API Machinery]

- Ignore context canceled from validate and mutate webhook ([#120020](https://github.com/kubernetes/kubernetes/pull/120020), [@divyasri537](https://github.com/divyasri537)) [SIG API Machinery]

- Kubelet: Added kubelet serving certificate metric `server_rotation_seconds` which is a histogram reporting the age of a just rotated serving certificate in seconds. ([#84534](https://github.com/kubernetes/kubernetes/pull/84534), [@sambdavidson](https://github.com/sambdavidson))