Vulnerability Details : CVE-2020-8562
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.
Products affected by CVE-2020-8562
- cpe:2.3:a:kubernetes:kubernetes:*:*:*:*:*:*:*:*
- cpe:2.3:a:kubernetes:kubernetes:*:*:*:*:*:*:*:*
- cpe:2.3:a:kubernetes:kubernetes:*:*:*:*:*:*:*:*
- cpe:2.3:a:kubernetes:kubernetes:1.21.0:*:*:*:*:*:*:*
Exploit prediction scoring system (EPSS) score for CVE-2020-8562
0.08%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 31 %
Percentile, the proportion of vulnerabilities that are scored at or less
CVSS scores for CVE-2020-8562
| Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source | First Seen |
|---|---|---|---|---|---|---|
|
3.5
|
LOW | AV:N/AC:M/Au:S/C:P/I:N/A:N |
6.8
|
2.9
|
NIST | |
|
2.2
|
LOW | CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:N |
0.7
|
1.4
|
Kubernetes | |
|
3.1
|
LOW | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N |
1.6
|
1.4
|
NIST |
CWE ids for CVE-2020-8562
-
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. This can cause the product to perform invalid actions when the resource is in an unexpected state.Assigned by:
- jordan@liggitt.net (Secondary)
- nvd@nist.gov (Primary)
References for CVE-2020-8562
-
https://security.netapp.com/advisory/ntap-20220225-0002/
CVE-2020-8562 Kubernetes Vulnerability in NetApp Products | NetApp Product SecurityThird Party Advisory
-
https://github.com/kubernetes/kubernetes/issues/101493
CVE-2020-8562: Bypass of Kubernetes API Server proxy TOCTOU · Issue #101493 · kubernetes/kubernetes · GitHubIssue Tracking;Mitigation;Third Party Advisory
-
https://groups.google.com/g/kubernetes-security-announce/c/-MFX60_wdOY
[Security Advisory] CVE-2020-8562: Bypass of Kubernetes API Server proxy TOCTOUMailing List;Third Party Advisory
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