Vulnerability · Published Feb 1, 2022 · Assigned by kubernetes
CVE-2020-8562Bypass of Kubernetes API Server proxy TOCTOU
Low 2.2
In plain English
A low-severity security flaw in Kubernetes from Kubernetes. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.2% (higher than 68% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
As mitigations to a report from 2019 and CVE-2020-8555, Kubernetes attempts to prevent proxied connections from accessing link-local or localhost networks when making user-driven connections to Services, Pods, Nodes, or StorageClass service providers. As part of this mitigation Kubernetes does a DNS name resolution check and validates that response IPs are not in the link-local (169.254.0.0/16) or localhost (127.0.0.0/8) range. Kubernetes then performs a second DNS resolution without validation for the actual connection. If a non-standard DNS server returns different non-cached responses, a user may be able to bypass the proxy IP restriction and access private networks on the control plane.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | kubernetes | 1.20.5+really1.20.2-1 | DEBIAN-CVE-2020-8562 |
| Debian:13 | kubernetes | 1.20.5+really1.20.2-1 | DEBIAN-CVE-2020-8562 |
| Debian:14 | kubernetes | 1.20.5+really1.20.2-1 | DEBIAN-CVE-2020-8562 |
| Go | k8s.io/kubernetes | no fix listed | GHSA-qh36-44jv-c8xj |
| Go | k8s.io/kubernetes | no fix listed | GO-2022-0617 |
| Go | k8s.io/kubernetes | no fix listed | GHSA-qh36-44jv-c8xj |
| Go | k8s.io/kubernetes | no fix listed | GHSA-qh36-44jv-c8xj |
| Go | k8s.io/kubernetes | no fix listed | GHSA-qh36-44jv-c8xj |
| Ubuntu:22.04:LTS | kubernetes | no fix listed | UBUNTU-CVE-2020-8562 |
| Ubuntu:24.04:LTS | kubernetes | no fix listed | UBUNTU-CVE-2020-8562 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Kubernetes | Kubernetes | 0 – before * |
Weakness: CWE-367 · Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:N
References
- https://kubernetes.io/blog/2026/05/26/reconciling-unfixed-kubernetes-cves/ x_refsource_MISC
- https://github.com/kubernetes/kubernetes/issues/101493 x_refsource_MISC
- https://groups.google.com/g/kubernetes-security-announce/c/-MFX60_wdOY x_refsource_MISC
- https://security.netapp.com/advisory/ntap-20220225-0002/ x_refsource_CONFIRM