CVE-2020-8555

Server Side Request Forgery (SSRF) in Kubernetes

The Kubernetes kube-controller-manager in versions v1.0-1.14, versions prior to v1.15.12, v1.16.9, v1.17.5, and version v1.18.0 are vulnerable to a Server Side Request Forgery (SSRF) that allows certain authorized users to leak up to 500 bytes of arbitrary information from unprotected endpoints within the master's host network (such as link-local or loopback services).

Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside. Typical impact: access to internal metadata services, internal APIs, or cloud credentials.

CVE-2020-8555 has a CVSS score of 6.3 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.18.1, 1.17.4, 1.16.9, 1.15.12); upgrading removes the vulnerable code path.

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1. What is CVE-2020-8555? CVE-2020-8555 is a medium-severity server-side request forgery (SSRF) vulnerability in k8s.io/kubernetes (go), affecting versions >= 1.18.0, < 1.18.1. It is fixed in 1.18.1, 1.17.4, 1.16.9, 1.15.12. Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside.
2. How severe is CVE-2020-8555? CVE-2020-8555 has a CVSS score of 6.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of k8s.io/kubernetes are affected by CVE-2020-8555? k8s.io/kubernetes (go) versions >= 1.18.0, < 1.18.1 is affected.
4. Is there a fix for CVE-2020-8555? Yes. CVE-2020-8555 is fixed in 1.18.1, 1.17.4, 1.16.9, 1.15.12. Upgrade to this version or later.
5. Is CVE-2020-8555 exploitable, and should I be worried? Whether CVE-2020-8555 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2020-8555 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2020-8555?
   • Upgrade k8s.io/kubernetes to 1.18.1 or later
   • Upgrade k8s.io/kubernetes to 1.17.4 or later
   • Upgrade k8s.io/kubernetes to 1.16.9 or later
   • Upgrade k8s.io/kubernetes to 1.15.12 or later

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