To upgrade, refer to this documentation _For core Kubernetes:_ https://kubernetes.io/docs/tasks/administer-cluster/cluster-management/#upgrading-a-cluster 

**Detection**:

Kubernetes Audit logs may indicate if the user name was misspelled to bypass the restriction placed on which user is a pod allowed to run as.

If you find evidence that this vulnerability has been exploited, please contact ******@****.***

**Additional Details**:

To upgrade, refer to this documentation _For core Kubernetes:_ https://kubernetes.io/docs/tasks/administer-cluster/cluster-management/#upgrading-a-cluster 

### Detection

Kubernetes Audit logs may indicate if the user name was misspelled to bypass the restriction placed on which user is a pod allowed to run as.

If you find evidence that this vulnerability has been exploited, please contact ******@****.***

#### Additional Details

* 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), [@ericchiang](https://github.com/ericchiang))

To upgrade, refer to this documentation _For core Kubernetes:_ https://kubernetes.io/docs/tasks/administer-cluster/cluster-management/#upgrading-a-cluster 

### Detection

Kubernetes Audit logs may indicate if the user name was misspelled to bypass the restriction placed on which user is a pod allowed to run as.

If you find evidence that this vulnerability has been exploited, please contact ******@****.***

#### Additional Details

- When configuring a JWT authenticator:
  
  If `username.expression` used 'claims.email', then 'claims.email_verified' must have been used in `username.expression` or `extra[*].valueExpression` or `claimValidationRules[*].expression`. An example claim validation rule expression that matches the validation automatically applied when `username.claim` is set to 'email' is 'claims.?email_verified.orValue(true) == true'.

  
  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.
  An example claim validation rule expression that matches the validation automatically
  applied when username.claim is set to 'email' is 'claims.?email_verified.orValue(true) == true'. 

* 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), [@ericchiang](https://github.com/ericchiang))

        * Nodes must use client credentials that place them in the `system:nodes` group with a username of `system:node:<nodeName>` in order to be authorized by the node authorizer (the credentials obtained by the kubelet via TLS bootstrapping satisfy these requirements)

* Fix the bug where StartedAt time is not reported for exited containers. ([#45977](https://github.com/kubernetes/kubernetes/pull/45977), [@yujuhong](https://github.com/yujuhong))
* Enable basic auth username rotation for GCI ([#44590](https://github.com/kubernetes/kubernetes/pull/44590), [@ihmccreery](https://github.com/ihmccreery))

## Changelog since v1.13.4

### Other notable changes

* Restores --username and --password flags to kubectl ([#75451](https://github.com/kubernetes/kubernetes/pull/75451), [@liggitt](https://github.com/liggitt))