Time-of-check Time-of-use (TOCTOU) Affecting kubernetes package, versions <1.20.5+really1.20.2-1


Severity

Recommended
0.0
low
0
10

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Threat Intelligence

EPSS
0.08% (35th percentile)

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  • Snyk IDSNYK-DEBIANUNSTABLE-KUBERNETES-1289550
  • published5 May 2021
  • disclosed1 Feb 2022

Introduced: 5 May 2021

CVE-2020-8562  (opens in a new tab)
CWE-367  (opens in a new tab)

How to fix?

Upgrade Debian:unstable kubernetes to version 1.20.5+really1.20.2-1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kubernetes package and not the kubernetes package as distributed by Debian. See How to fix? for Debian:unstable relevant fixed versions and status.

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.

CVSS Scores

version 3.1