What’s Vulnerable › Vulnerabilities

CVE-2020-8557: Kubernetes node disk Denial of Service by writing to container /etc/hosts

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-07-23 · updated 2026-06-17
• Weakness: CWE-400

Description

The Kubernetes kubelet component in versions 1.1-1.16.12, 1.17.0-1.17.8 and 1.18.0-1.18.5 do not account for disk usage by a pod which writes to its own /etc/hosts file. The /etc/hosts file mounted in a pod by kubelet is not included by the kubelet eviction manager when calculating ephemeral storage usage by a pod. If a pod writes a large amount of data to the /etc/hosts file, it could fill the storage space of the node and cause the node to fail.

Affected products

• Kubernetes: before 1.16.13; from 1.17.0 before 1.17.9; from 1.18.0 before 1.18.6 — fixed in 1.16.13, 1.17.9, 1.18.6

How to fix

Upgrade to a fixed version: Kubernetes 1.16.13, 1.17.9, 1.18.6. Check the vendor advisory for mitigations.

References

• https://github.com/kubernetes/kubernetes/issues/93032
• https://groups.google.com/g/kubernetes-security-announce/c/cB_JUsYEKyY/m/vVSO61AhBwAJ
• https://security.netapp.com/advisory/ntap-20200821-0002/
• https://github.com/kubernetes/kubernetes/issues/93032
• https://groups.google.com/g/kubernetes-security-announce/c/cB_JUsYEKyY/m/vVSO61AhBwAJ
• https://security.netapp.com/advisory/ntap-20200821-0002/

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