A security issue was discovered in Kubernetes where actors that control the responses of MutatingWebhookConfiguration or ValidatingWebhookConfiguration requests are able to redirect kube-apiserver requests to private networks of the apiserver. If that user can view kube-apiserver logs when the log level is set to 10, they can view the redirected responses and headers in the logs.
CVE-2020-8561
Score 4.1 from GitHub Security Advisory published 2021-09-21. NVD baseline CVSS 4.1; sources differ by 0.0.
- Lower severity and no public exploit yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 4.1
- EG Score
- 4.1(medium)
- EPSS
- 77.9%
- KEV
- Not listed
Published
September 20, 2021
Last Modified
June 1, 2026
References (7)
- jordan@liggitthttps://github.com/kubernetes/kubernetes/issues/104720
- jordan@liggitthttps://groups.google.com/g/kubernetes-security-announce/c/RV2IhwcrQsY
- jordan@liggitthttps://kubernetes.io/blog/2026/05/26/reconciling-unfixed-kubernetes-cves/
- jordan@liggitthttps://security.netapp.com/advisory/ntap-20211014-0002/
- af854a3a-2127-422b-91ae-364da2661108https://github.com/kubernetes/kubernetes/issues/104720
- af854a3a-2127-422b-91ae-364da2661108https://groups.google.com/g/kubernetes-security-announce/c/RV2IhwcrQsY
- af854a3a-2127-422b-91ae-364da2661108https://security.netapp.com/advisory/ntap-20211014-0002/
Vendor Advisories for CVE-2020-8561(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Patch Availability(1)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| go | k8s.io/kubernetes | — | ghsa |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Affected Packages
(1 across 1 ecosystem)
Go(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| k8s.io/kubernetes | — | — | — |
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
All Vendor Advisories
(1)
Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.
Data Freshness Timeline
(refreshed 10× in last 7d / 45× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-11 08:25 UTCEPSS rescore
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- 2026-06-30 13:00 UTCOSV refresh
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- 2026-06-23 21:31 UTCEPSS rescore
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- 2026-06-12 21:10 UTCOSV refresh
- 2026-06-11 13:58 UTCEPSS rescore
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- 2026-05-27 13:39 UTCEPSS rescore
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- 2026-05-26 13:42 UTCEPSS rescore
- 2026-05-26 13:42 UTCEPSS rescore
- 2026-05-26 10:06 UTCEG score recompute
- 2026-05-26 10:06 UTCVendor advisory
- 2026-05-26 10:06 UTCGHSA enrichment
- 2026-05-26 07:17 UTCEPSS rescore
- 2026-05-26 07:17 UTCEPSS rescore
Frequently asked(5)
What is CVE-2020-8561?
When was CVE-2020-8561 disclosed?
Is CVE-2020-8561 actively exploited?
What is the CVSS score of CVE-2020-8561?
How do I remediate CVE-2020-8561?
Dependency Blast Radius
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