CVE-2026-106487: @backstage/plugin-kubernetes-backend - Unsupported Catalog Cluster Authentication Mode Vulnerability
Summary
CVE-2026-106487: Backstage: Unsupported catalog cluster authentication mode in kubernetes backend. Affects @backstage/plugin-kubernetes-backend versions < 0.21.10. Fixed in 0.21.10. How to fix ↓
Check if this vulnerability affects your application
Upload a manifest or SBOM and we'll show whether you're affected, plus every other risky package in the same scan.
No signup required · Results in about 60 seconds
Background
The @backstage/plugin-kubernetes-backend package is a plugin for the Backstage platform, which is designed to facilitate the management and discovery of Kubernetes resources. This plugin allows users to interact with Kubernetes clusters, enabling them to view and manage resources effectively. However, it has been found to have a vulnerability related to unsupported authentication modes when using catalog cluster discovery, which can expose sensitive Kubernetes resources.
Vulnerability Detail
The vulnerability arises when catalog contributors are able to create or modify 'kubernetes-cluster' Resource entities. If the necessary endpoint permissions and pod RBAC are configured, the backend can utilize its local in-cluster identity. This could lead to the exposure of Kubernetes resources that are readable by that identity. The credential is only used with the local in-cluster API endpoint and is not transmitted to the catalog-supplied endpoint, making it a potential security risk.
How To Fix
Minimum fixed version
0.21.10
This is the first release that contains the fix.
npm install @backstage/plugin-kubernetes-backend@0.21.10Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary measure, avoid configuring service account authentication through catalog-provided clusters. Instead, utilize the supported static configuration method when service account authentication is necessary. Additionally, restrict catalog ingestion to prevent untrusted users from creating or altering Kubernetes cluster Resource entities.
Conclusion
In summary, CVE-2026-106487 affects the @backstage/plugin-kubernetes-backend package, posing a risk of unauthorized access to Kubernetes resources. It is crucial to update to the patched version 0.21.10 or later and implement the suggested workarounds to safeguard your application.
See every vulnerability recorded for @backstage/plugin-kubernetes-backend →
FAQ
CVE-2026-106487 is a vulnerability in the @backstage/plugin-kubernetes-backend package that allows unauthorized access to Kubernetes resources due to unsupported authentication modes.
The vulnerability can expose sensitive Kubernetes resources to unauthorized users, potentially leading to data breaches or unauthorized modifications.
You can use the Vulert playground at Vulert Scanner to check if your application is affected by this vulnerability without needing to sign up.
If immediate updates are not possible, implement the recommended workarounds to mitigate the risk until you can apply the patch.
The CVSS score of this vulnerability is 3.5, indicating a low severity level.
References
Related vulnerabilities
Recent vulnerabilities recorded for @backstage/plugin-kubernetes-backend.
