URL Redirection to Untrusted Site ('Open Redirect')
The Kubernetes kube-apiserver in versions v1.6-v1.15, and versions prior to v1.16.13, v1.17.9 and v1.18.6 are vulnerable to an unvalidated redirect on proxied upgrade requests that could allow an attacker to escalate privileges from a node compromise to a full cluster compromise.
CWE-601 - Open Redirect
An open redirect attack employs a URL parameter, HTML refresh tags, or a DOM based location change to exploit the trust of a vulnerable domain to direct the users to a malicious website. The attack could lead to higher severity vulnerabilities such as unauthorized access control, account takeover, XSS, and more.