- Structured Authentication Configuration now supports configuring multiple JWT authenticators. The maximum allowed JWT authenticators in the authentication configuration is 64. ([#123431](https://github.com/kubernetes/kubernetes/pull/123431), [@aramase](https://github.com/aramase))

- Introduced a new metric `kubelet_admission_rejections_total` to track the number of pods rejected during admission. ([#128556](https://github.com/kubernetes/kubernetes/pull/128556), [@AnishShah](https://github.com/AnishShah))

- Added support for specifying `controlplane` or `cluster` egress selectors in JWT authenticators via the `issuer.egressSelectorType` field in the `AuthenticationConfiguration.jwt` array. If unset, the previous behavior of using no egress selector is preserved. This functionality requires the `StructuredAuthenticationConfigurationEgressSelector`...

* kube-apiserver: the OpenID Connect authenticator can now verify ID Tokens signed with JOSE algorithms other than RS256 through the --oidc-signing-algs flag. ([#58544](https://github.com/kubernetes/kubernetes/pull/58544), [@ericchiang](https://github.com/ericchiang))

few seconds. ([#50258](https://github.com/kubernetes/kubernetes/pull/50258), [@liggitt](https://github.com/liggitt))

* The OpenID Connect authenticator can now use a custom prefix, or omit the default prefix, for username and groups claims through the --oidc-username-prefix and --oidc-groups-prefix flags. For example, the authenticator can map a user with the username "jane" to "google:jane" by supplying the "google:" username prefix. ([#50875](https://github.com/kubernetes/kubernetes/pull/50875),...

* The OpenID Connect authenticator can now use a custom prefix, or omit the default prefix, for username and groups claims through the --oidc-username-prefix and --oidc-groups-prefix flags. For example, the authenticator can map a user with the username "jane" to "google:jane" by supplying the "google:" username prefix. ([#50875](https://github.com/kubernetes/kubernetes/pull/50875),...

* Exec authenticator plugin supports TLS client certificates. ([#61803](https://github.com/kubernetes/kubernetes/pull/61803), [@awly](https://github.com/awly))

- Fixed the example validation rule in godoc:
  
  When configuring a JWT authenticator:
  
  If username.expression uses 'claims.email', then 'claims.email_verified' must be used in
  username.expression or extra[*].valueExpression or claimValidationRules[*].expression.

- Adds metrics for the delegated authenticator used by extension APIs that delegate authentication logic to the Kube API server. ([#99364](https://github.com/kubernetes/kubernetes/pull/99364), [@p0lyn0mial](https://github.com/p0lyn0mial))

- Increased `CSINodeIDMaxLength` from 128 bytes to 192 bytes. ([#98753](https://github.com/kubernetes/kubernetes/pull/98753), [@Jiawei0227](https://github.com/Jiawei0227))
- Kube-apiserver: The OIDC authenticator no longer waits 10 seconds before attempting to fetch the metadata required to verify tokens. ([#97693](https://github.com/kubernetes/kubernetes/pull/97693), [@enj](https://github.com/enj)) [SIG API Machinery and Auth]