CVE-2020-8562
Bypass of Kubernetes API Server proxy TOCTOU
- State
- Published
- Severity
- 2.2 Low
- Published
- Feb 1, 2022
- Updated
- Jun 1, 2026
- Reserved
- Feb 3, 2020
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 2.2 Low | CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:N | kubernetes |
Weaknesses
- CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition
Affected Products
| Product | Versions |
|---|---|
KubernetesKubernetes |
|
References
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