CVE-2020-8562: K8s.io/kubernetes Potential Proxy IP Restriction Bypass Vulnerability
LOWCVE-2020-8562 is a LOW (CVSS 3.1) potential proxy ip restriction bypass vulnerability (CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition) affecting K8s.io/kubernetes libraries in the Go ecosystem. The issue involves potential proxy ip restriction bypass in kubernetes. Remediation is available in the latest vendor maintenance releases.
CVE-2020-8562 at a Glance
Security Impact
CVSS: 3.1
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N).
How to Fix CVE-2020-8562
To remediate this vulnerability, upgrade all affected K8s.io/kubernetes dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
Upgrade k8s.io/kubernetes to Latest secure releaseUpgrade k8s.io/kubernetes to Latest secure releaseUpgrade k8s.io/kubernetes to Latest secure releaseUpgrade k8s.io/kubernetes to Latest secure releaseRun the following command in your project directory to verify that all resolved dependencies use the patched release:
inspect dependencies for k8s.io/kubernetesHow to Check if You Are Affected
To determine whether your application is affected by CVE-2020-8562, inspect your project dependencies for K8s.io/kubernetes:
inspect dependencies for k8s.io/kubernetesAnalyze the terminal output to locate any version of K8s.io/kubernetes in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.
Note: Verify declared build manifests and deployed runtime container environments.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition, where the product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check. In K8s.io/kubernetes, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2020-8562 Affected K8s.io/kubernetes Versions
4 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
k8s.io/kubernetes
|
Go |
≥ 1.21.0
≤ 1.21.1
|
|
|
k8s.io/kubernetes
|
Go |
≥ 1.20.0
≤ 1.20.7
|
|
|
k8s.io/kubernetes
|
Go |
≥ 1.19.0
≤ 1.19.11
|
|
|
k8s.io/kubernetes
|
Go |
≤ 1.18.19
|
|
References
Frequently Asked Questions
What is CVE-2020-8562?
Which K8s.io/kubernetes versions are affected?
What version fixes CVE-2020-8562?
Is k8s.io/kubernetes affected?
What is the CVSS score of CVE-2020-8562?
What CWE is associated with CVE-2020-8562?
How can I check Go dependencies for CVE-2020-8562?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-qh36-44jv-c8xj",
"modified" : "2026-06-09T10:51:51Z",
"published" : "2022-02-02T00:01:58Z",
"aliases" : [ "CVE-2020-8562" ],
"summary" : "Potential proxy IP restriction bypass in Kubernetes",
"details" : "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. All versions of Kubernetes are impacted, and there is no fix in place.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Go",
"name" : "k8s.io/kubernetes"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "1.21.0"
}, {
"last_affected" : "1.21.1"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Go",
"name" : "k8s.io/kubernetes"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "1.20.0"
}, {
"last_affected" : "1.20.7"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Go",
"name" : "k8s.io/kubernetes"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "1.19.0"
}, {
"last_affected" : "1.19.11"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Go",
"name" : "k8s.io/kubernetes"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"last_affected" : "1.18.19"
} ]
} ]
} ],
"references" : [ {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-8562"
}, {
"type" : "WEB",
"url" : "https://github.com/kubernetes/kubernetes/issues/101493"
}, {
"type" : "WEB",
"url" : "https://github.com/kubernetes/kubernetes/issues/101493#issuecomment-2272095629"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/kubernetes/kubernetes"
}, {
"type" : "WEB",
"url" : "https://groups.google.com/g/kubernetes-security-announce/c/-MFX60_wdOY"
}, {
"type" : "WEB",
"url" : "https://kubernetes.io/blog/2026/05/26/reconciling-unfixed-kubernetes-cves"
}, {
"type" : "WEB",
"url" : "https://security.netapp.com/advisory/ntap-20220225-0002"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-367" ],
"severity" : "LOW",
"github_reviewed" : true,
"github_reviewed_at" : "2022-02-03T17:52:40Z",
"nvd_published_at" : "2022-02-01T11:15:00Z"
}
}