CVE-2020-8553: Kubernetes ingress-nginx Compromise of auth via subset/superset namespace names

Severity: medium (CVSS 5.9 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.9% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-07-29 · updated 2026-06-17
Weakness: CWE-73

Description

The Kubernetes ingress-nginx component prior to version 0.28.0 allows a user with the ability to create namespaces and to read and create ingress objects to overwrite the password file of another ingress which uses nginx.ingress.kubernetes.io/auth-type: basic and which has a hyphenated namespace or secret name.

Affected products

Kubernetes ingress-nginx: before 0.28.0 — fixed in 0.28.0

How to fix

Upgrade to a fixed version: Kubernetes ingress-nginx 0.28.0. Check the vendor advisory for mitigations.

References

https://github.com/kubernetes/ingress-nginx/issues/5126
https://github.com/kubernetes/ingress-nginx/issues/5126

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