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Medium, CVSS 5.5

Denial of service in Kubernetes

CVE-2020-8557GHSA-55qj-gj3x-jq9r

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (k8s.io/kubernetes/pkg/kubelet 1.18.6, 1.17.9, 1.16.13), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
5.5 · CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS
  • CVE-2020-8557: 0.43% estimated exploitation activity in the next 30 days; percentile 37.79 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

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.

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 1 · created ·

    Published from ghsa record GHSA-55qj-gj3x-jq9r

Agent brief

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2020-8557

Advisory: Denial of service in Kubernetes
IDs: CVE-2020-8557, GHSA-55qj-gj3x-jq9r
Record: https://patchnext.com/advisories/cve-2020-8557 (revision 1, source checked 26 Oct 2026, 15:04 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: k8s.io/kubernetes/pkg/kubelet 1.18.6, 1.17.9, 1.16.13. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go k8s.io/kubernetes/pkg/kubelet: affected >= 1.1.0, < 1.16.13; >= 1.17.0, < 1.17.9; >= 1.18.0, < 1.18.6; fixed in 1.16.13, 1.18.6, 1.17.9

## Suggested inspection (read-only)
- Go k8s.io/kubernetes/pkg/kubelet: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on k8s.io/kubernetes/pkg/kubelet.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-55qj-gj3x-jq9r (GitHub-reviewed advisory GHSA-55qj-gj3x-jq9r lists affected ranges: Go k8s.io/kubernetes/pkg/kubelet >=1.1.0 =1.17.0 =1.18.0 <1.18.6)

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