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Medium, CVSS 6.8

Privilege Escalation in Kubernetes

CVE-2020-8559GHSA-33c5-9fx5-fvjm

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (k8s.io/kubernetes 1.18.7, 1.17.9, 1.16.13; k8s.io/apimachinery 0.18.7, 0.17.9, 0.16.13), 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

  • Go k8s.io/kubernetes

    Affected
    < 1.16.13>= 1.17.0, < 1.17.9>= 1.18.0, < 1.18.7
    Fixed in
    1.18.7, 1.16.13, 1.17.9

  • Go k8s.io/apimachinery

    Affected
    < 0.16.13>= 0.17.0, < 0.17.9>= 0.18.0, < 0.18.7
    Fixed in
    0.16.13, 0.17.9, 0.18.7

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
6.8 · CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:H
EPSS
  • CVE-2020-8559: 6.10% estimated exploitation activity in the next 30 days; percentile 93.44 (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 kube-apiserver in versions v1.6-v1.15, and versions prior to v1.16.13, v1.17.9 and v1.18.7 are vulnerable to an unvalidated redirect on proxied upgrade requests that could allow an attacker to escalate privileges from a node compromise to a full cluster compromise.

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

    Published from ghsa record GHSA-33c5-9fx5-fvjm

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-2020-8559

Advisory: Privilege Escalation in Kubernetes
IDs: CVE-2020-8559, GHSA-33c5-9fx5-fvjm
Record: https://patchnext.com/advisories/cve-2020-8559 (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 6.8)
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 1.18.7, 1.17.9, 1.16.13; k8s.io/apimachinery 0.18.7, 0.17.9, 0.16.13. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go k8s.io/kubernetes: affected < 1.16.13; >= 1.17.0, < 1.17.9; >= 1.18.0, < 1.18.7; fixed in 1.18.7, 1.16.13, 1.17.9
- Go k8s.io/apimachinery: affected < 0.16.13; >= 0.17.0, < 0.17.9; >= 0.18.0, < 0.18.7; fixed in 0.16.13, 0.17.9, 0.18.7

## Suggested inspection (read-only)
- Go k8s.io/kubernetes: check the installed version with your package manager.
- Go k8s.io/apimachinery: 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, k8s.io/apimachinery.
- 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-33c5-9fx5-fvjm (GitHub-reviewed advisory GHSA-33c5-9fx5-fvjm lists affected ranges: Go k8s.io/apimachinery >=0 =0.17.0 =0.18.0 =0 =1.17.0 =1.18.0 <1.18.7)

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