return
	}

	// It is required that parent user be set.
	if res.Success.User == "" {
		writeSTSErrorResponse(ctx, w, ErrSTSUpstreamError, errors.New("A valid user was not returned by the authenticator."))
		return
	}

	// Expiry is set as minimum of requested value and value allowed by auth
	// plugin.
	expiry := res.Success.MaxValiditySeconds
	if durationParam != "" && requestedDuration < expiry {

- 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

* 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),...

* 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))

- The JWT authenticator in `kube-apiserver` now reports the following metrics when the `StructuredAuthenticationConfiguration` feature gate is enabled:
  - `apiserver_authentication_jwt_authenticator_jwks_fetch_last_timestamp_seconds`

* 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))

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

* 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),...