- The API server now detects and fails on startup if there are conflicting issuers between JWT authenticators and service account configurations. Previously, such configurations would run but could be inconsistently effective depending on the credential. ([#123561](https://github.com/kubernetes/kubernetes/pull/123561), [@enj](https://github.com/enj))

* Security/Auth
  * L7 LB controller and disk attach controllers run on master, so nodes do not need those privileges.
  * Setting TLS1.2 minimum
  * `kubectl create secret tls` command
  * Webhook Token Authenticator
  * **beta** PodSecurityPolicy objects limits use of security-sensitive features by pods.
* Kubectl
  * Display line number on JSON errors
  * Add flag -t as shorthand for --tty
* Resources

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),...

* Reduce time needed to attach Azure disks ([#40066](https://github.com/kubernetes/kubernetes/pull/40066), [@codablock](https://github.com/codablock))
* Fixes request header authenticator by presenting the request header client CA so that the front proxy will authenticate using its client certificate. ([#40301](https://github.com/kubernetes/kubernetes/pull/40301), [@deads2k](https://github.com/deads2k))

* 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))

* Add support for --image-pull-policy to 'kubectl run' ([#30614](https://github.com/kubernetes/kubernetes/pull/30614), [@AdoHe](https://github.com/AdoHe))
* x509 authenticator: get groups from subject's organization field ([#30392](https://github.com/kubernetes/kubernetes/pull/30392), [@ericchiang](https://github.com/ericchiang))

- 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.

* 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),...

- 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]

- 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))