What’s Vulnerable › Vulnerabilities

CVE-2020-8561: Webhook redirect in kube-apiserver

• Severity: medium (CVSS 4.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-09-20 · updated 2026-06-17
• Weakness: CWE-441

Description

A security issue was discovered in Kubernetes where actors that control the responses of MutatingWebhookConfiguration or ValidatingWebhookConfiguration requests are able to redirect kube-apiserver requests to private networks of the apiserver. If that user can view kube-apiserver logs when the log level is set to 10, they can view the redirected responses and headers in the logs.

Affected products

• Kubernetes: 1.20.11, 1.21.5, 1.22.2

References

• https://github.com/kubernetes/kubernetes/issues/104720
• https://groups.google.com/g/kubernetes-security-announce/c/RV2IhwcrQsY
• https://kubernetes.io/blog/2026/05/26/reconciling-unfixed-kubernetes-cves/
• https://security.netapp.com/advisory/ntap-20211014-0002/
• https://github.com/kubernetes/kubernetes/issues/104720
• https://groups.google.com/g/kubernetes-security-announce/c/RV2IhwcrQsY
• https://security.netapp.com/advisory/ntap-20211014-0002/

Get alerted when CVE-2020-8561 or the next vulnerability affects your stack