# CVE-2026-106563: Backstage improper entity validation in Kubernetes services endpoint

Source: https://junglewise.ai/threats/cve-2026-106563-backstage-improper-entity-validation-in-deprecated-kubernetes  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-07. Updated: 2026-10-07  
License: CC BY 4.0 with a link back

CVE-2026-106563 · Severity: medium · CVSS 5.3 · Published 2026-10-07

Backstage is an open platform for building internal developer portals. An authenticated user with read access to Kubernetes could exploit improper validation in a deprecated endpoint to view Kubernetes workload metadata beyond their intended scope, gaining unauthorized visibility into container and infrastructure details across clusters.

Technologies: [Linuxfoundation Backstage\](https://junglewise.ai/threats/technologies/backstage), [@backstage/plugin-kubernetes-backend (npm)](https://junglewise.ai/threats/technologies/backstage-plugin-kubernetes-backend). Vendors: [Backstage](https://junglewise.ai/threats/vendors/backstage), [Linuxfoundation](https://junglewise.ai/threats/vendors/linuxfoundation), [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2026-106563 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-106563 being exploited in the wild.

**How severe is CVE-2026-106563?** Medium severity, with a CVSS score of 5.3, published 7 October 2026.

**Which products and versions are affected?** Backstage Plugin-Kubernetes-Backend < 0.21.8; @backstage/plugin-kubernetes-backend (npm) < 0.21.8, SEMVER:introduced=0,fixed=0.21.8.

**Is there a fix for CVE-2026-106563?** Yes. @backstage/plugin-kubernetes-backend (npm): upgrade to 0.21.8 or later. Until then: Disable the deprecated /services/:serviceId route by deploying a custom Kubernetes router that omits it, or restrict access to the kubernetes.resources.read permission to limit which users can reach the endpoint. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-106563 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-106563?** Check whether you run Backstage Plugin-Kubernetes-Backend, Linuxfoundation Backstage\, Linuxfoundation Plugin-Kubernetes-Backend or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- @backstage/plugin-kubernetes-backend (npm): upgrade to 0.21.8 or later

  ```sh
  npm install @backstage/plugin-kubernetes-backend@0.21.8
  ```


Disable the deprecated /services/:serviceId route by deploying a custom Kubernetes router that omits it, or restrict access to the kubernetes.resources.read permission to limit which users can reach the endpoint.

## Technical details

The vulnerability exists in the deprecated /services/:serviceId endpoint of the Kubernetes plugin backend, where insufficient entity validation allows an authenticated attacker to supply crafted entity data to access Kubernetes object metadata across configured clusters. The attack requires network access, authentication, and low privileges (kubernetes.resources.read permission), but has high attack complexity. The exposure is limited to read-only metadata access with no data modification or availability impact.

## Affected products

- Backstage plugin-kubernetes-backend < 0.21.8

## Identifiers

- CVE-2026-106563
- GHSA-r9ph-3637-55px

## Timeline

- 2026-08-28: disclosed
- 2026-10-07: advisory

## References

- [https://github.com/backstage/backstage/security/advisories/GHSA-r9ph-3637-55px](https://github.com/backstage/backstage/security/advisories/GHSA-r9ph-3637-55px)

## Related threats

- [Backstage incorrect authorization in search engine permission filtering](https://junglewise.ai/threats/cve-2026-106562-backstage-has-incorrect-authorization-in-search-engine)
- [Backstage Kubernetes plugin sensitive information disclosure in resource queries](https://junglewise.ai/threats/cve-2026-106561-backstage-has-a-sensitive-information-disclosure-in-kubernetes)
- [Backstage plugin-scaffolder-backend-module-confluence-to-markdown path traversal](https://junglewise.ai/threats/cve-2026-106560-backstage-improper-repository-path-validation-in-a-scaffolder)
- [Backstage Confluence to Markdown scaffolder input validation bypass](https://junglewise.ai/threats/cve-2026-106559-backstage-improper-input-validation-in-confluence-to-markdown)
- [Backstage: Unsupported catalog cluster authentication mode in kubernetes backend](https://junglewise.ai/threats/cve-2026-106487-backstage-is-an-open-framework-for-building-developer-portals)