How severe is CVE-2020-8561?

CVE-2020-8561 has a CVSS 3.x base score of 4.1, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2020-8561 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (78th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-8561?

CVE-2020-8561 primarily affects Kubernetes. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-8561?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2020-8561 published?

CVE-2020-8561 was published on 2021-09-20 and last updated on 2026-06-17.

CVE-2020-8561

CVE-2020-8561 is a medium-severity vulnerability in Kubernetes with a CVSS 3.x base score of 4.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-610.

Key facts

Severity: Medium (CVSS 3.x base score 4.1)
CVSS v2: 4.0
EPSS exploit prediction: 2% (78th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-610
Affected product: Kubernetes
Published: 2021-09-20
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2020-8561?: 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.
How severe is CVE-2020-8561?: CVE-2020-8561 has a CVSS 3.x base score of 4.1, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2020-8561 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (78th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-8561?: CVE-2020-8561 primarily affects Kubernetes. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-8561?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-8561 published?: CVE-2020-8561 was published on 2021-09-20 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:kubernetes:kubernetes:1.20.11:-:*:*:*:*:*:*
cpe:2.3:a:kubernetes:kubernetes:1.21.5:-:*:*:*:*:*:*
cpe:2.3:a:kubernetes:kubernetes:1.22.2:-:*:*:*:*:*:*

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