CVE-2020-8558 Kubernetes node setting allows for neighboring hosts to bypass localhost boundary

What is CVE-2020-8558?

CVE-2020-8558 is a medium-severity vulnerability in Kubernetes Kubernetes, published on 27 Jul 2020.

Official description

The Kubelet and kube-proxy components in versions 1.1.0-1.16.10, 1.17.0-1.17.6, and 1.18.0-1.18.3 were found to contain a security issue which allows adjacent hosts to reach TCP and UDP services bound to 127.0.0.1 running on the node or in the node's network namespace. Such a service is generally thought to be reachable only by other processes on the same host, but due to this defeect, could be reachable by other hosts on the same LAN as the node, or by containers running on the same node as the service.

Weakness: CWE-420

Which versions are affected by CVE-2020-8558?

7 open source packages ship an affected version, including k8s.io/kubernetes. It affects 1 product.

Products include Kubernetes Kubernetes.

How do I fix CVE-2020-8558?

Upgrade k8s.io/kubernetes to a fixed version for your release line: 1.16.11, 1.17.7 or 1.18.4.

Is CVE-2020-8558 being exploited?

There is no known exploitation of CVE-2020-8558 in the wild and no public exploit code.

Public exploit code: 2 proofs of concept on GitHub.

Other vulnerabilities in Kubernetes Kubernetes

• CVE-2018-1002105 Privilege Escalation in Kubernetes Critical 9.8
• CVE-2017-1000056 Kubernetes Privilege Escalation Critical 9.8
• CVE-2016-1906 Authorization bypass in Openshift Critical 9.8
• CVE-2023-3676 Kubernetes - Windows nodes - Insufficient input sanitization leads to privilege escalation High 8.8
• CVE-2023-3955 Kubernetes - Windows nodes - Insufficient input sanitization leads to privilege escalation High 8.8

All Kubernetes Kubernetes vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as CLEANSTART-2025-WT23235, DEBIAN-CVE-2020-8558, GHSA-wqv3-8cm6-h6wg, GO-2022-0885, RHSA-2020:3183.