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.
No analysis available yet.
Remediation
Vendor Workaround
If this issue affects your clusters’ 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
Tracking
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Advisories
| Source | ID | Title |
|---|---|---|
EUVD |
EUVD-2022-1153 | 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. |
Github GHSA |
GHSA-qh36-44jv-c8xj | Potential proxy IP restriction bypass in Kubernetes |
References
History
Fri, 11 Jul 2025 13:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
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Status: PUBLISHED
Assigner: kubernetes
Published:
Updated: 2024-09-16T17:08:37.065Z
Reserved: 2020-02-03T00:00:00.000Z
Link: CVE-2020-8562
No data.
Status : Modified
Published: 2022-02-01T11:15:10.903
Modified: 2024-11-21T05:39:02.180
Link: CVE-2020-8562
OpenCVE Enrichment
No data.
Weaknesses
EUVD
Github GHSA