CVE-2020-8562 (GCVE-0-2020-8562)
Vulnerability from cvelistv5
Published
2022-02-01 10:33
Modified
2026-06-01 21:45
Severity ?
VLAI Severity ?
EPSS score ?
CWE
- CWE-367 - Time-of-check Time-of-use (TOCTOU) Race Condition
Summary
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.
References
| URL | Tags | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
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Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Kubernetes | Kubernetes |
Version: 0 ≤ |
{
"containers": {
"adp": [
{
"providerMetadata": {
"dateUpdated": "2024-08-04T10:03:46.172Z",
"orgId": "af854a3a-2127-422b-91ae-364da2661108",
"shortName": "CVE"
},
"references": [
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "https://github.com/kubernetes/kubernetes/issues/101493"
},
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "https://groups.google.com/g/kubernetes-security-announce/c/-MFX60_wdOY"
},
{
"tags": [
"x_refsource_CONFIRM",
"x_transferred"
],
"url": "https://security.netapp.com/advisory/ntap-20220225-0002/"
}
],
"title": "CVE Program Container"
}
],
"cna": {
"affected": [
{
"product": "Kubernetes",
"vendor": "Kubernetes",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "0",
"versionType": "semver"
}
]
}
],
"credits": [
{
"lang": "en",
"value": "Javier Provecho"
}
],
"datePublic": "2021-05-04T00:00:00.000Z",
"descriptions": [
{
"lang": "en",
"value": "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."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "HIGH",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 2.2,
"baseSeverity": "LOW",
"confidentialityImpact": "LOW",
"integrityImpact": "NONE",
"privilegesRequired": "HIGH",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:N",
"version": "3.1"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-367",
"description": "CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-06-01T21:45:40.339Z",
"orgId": "a6081bf6-c852-4425-ad4f-a67919267565",
"shortName": "kubernetes"
},
"references": [
{
"tags": [
"x_refsource_MISC"
],
"url": "https://kubernetes.io/blog/2026/05/26/reconciling-unfixed-kubernetes-cves/"
},
{
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/kubernetes/kubernetes/issues/101493"
},
{
"tags": [
"x_refsource_MISC"
],
"url": "https://groups.google.com/g/kubernetes-security-announce/c/-MFX60_wdOY"
},
{
"tags": [
"x_refsource_CONFIRM"
],
"url": "https://security.netapp.com/advisory/ntap-20220225-0002/"
}
],
"source": {
"defect": [
"https://github.com/kubernetes/kubernetes/issues/101493"
],
"discovery": "EXTERNAL"
},
"title": "Bypass of Kubernetes API Server proxy TOCTOU",
"workarounds": [
{
"lang": "en",
"value": "If this issue affects your clusters\u2019 control planes, you can use dnsmasq for name resolution and configure the min-cache-ttl and neg-ttl parameters to a low non-zero value to enforce cached replies for proxied connections"
}
],
"x_generator": {
"engine": "Vulnogram 0.0.9"
}
}
},
"cveMetadata": {
"assignerOrgId": "a6081bf6-c852-4425-ad4f-a67919267565",
"assignerShortName": "kubernetes",
"cveId": "CVE-2020-8562",
"datePublished": "2022-02-01T10:33:00.317Z",
"dateReserved": "2020-02-03T00:00:00.000Z",
"dateUpdated": "2026-06-01T21:45:40.339Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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