Backstage up to 0.21.9 @backstage/plugin-kubernetes-backend improper authorization

Summaryinfo

A vulnerability has been found in Backstage up to 0.21.9 and classified as problematic. Impacted is an unknown function of the component @backstage/plugin-kubernetes-backend. The manipulation leads to improper authorization. This vulnerability is listed as CVE-2026-106487. The attack may be initiated remotely. There is no available exploit. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in Backstage up to 0.21.9. It has been rated as problematic. This issue affects an unknown part of the component @backstage/plugin-kubernetes-backend. The manipulation with an unknown input leads to a improper authorization vulnerability. Using CWE to declare the problem leads to CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. Impacted is confidentiality. The summary by CVE is:

Backstage is an open framework for building developer portals. Prior to 0.21.10, the @backstage/plugin-kubernetes-backend package is affected by unsupported catalog cluster authentication mode in kubernetes backend. Deployments using catalog cluster discovery may be affected when catalog contributors can create or modify kubernetes-cluster Resource entities. With the required endpoint permissions and pod RBAC, the backend can use its local in-cluster identity, potentially exposing Kubernetes resources readable by that identity. The credential is used only with the local in-cluster API endpoint and is not sent to the catalog-supplied endpoint. This issue is fixed in version 0.21.10.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-106487 since 10/06/2026. The exploitation is known to be easy. The attack may be initiated remotely. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1548.002 according to MITRE ATT&CK.

Upgrading to version 0.21.10 eliminates this vulnerability.

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Productinfo

Name

• Backstage

Version

• 0.21.0
• 0.21.1
• 0.21.2
• 0.21.3
• 0.21.4
• 0.21.5
• 0.21.6
• 0.21.7
• 0.21.8
• 0.21.9

Website

• Product: https://github.com/backstage/backstage/

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