CVE-2026-106563 Backstage: Improper entity validation in deprecated Kubernetes services endpoint
Authenticated users can bypass entity validation to read Kubernetes workload metadata beyond their intended scope via a deprecated endpoint.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-106563?
CVE-2026-106563 is a medium-severity missing authorization vulnerability in Linuxfoundation Backstage, published on 7 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Backstage is an open framework for building developer portals. Prior to 0.21.8, the @backstage/plugin-kubernetes-backend package is affected by improper entity validation in deprecated kubernetes services endpoint. An authenticated user with Kubernetes read permissions could access Kubernetes workload data beyond their intended scope by supplying crafted entity data to the deprecated services endpoint. The exposure is limited to read-only access to Kubernetes object metadata across configured clusters. This issue is fixed in version 0.21.8.
Which versions are affected by CVE-2026-106563?
2 open source packages ship an affected version, including @backstage/plugin-kubernetes-backend. It affects 2 products.
| Package | Affected | Fixed in |
|---|---|---|
@backstage/plugin-kubernetes-backend npm | All versions | 0.21.8 |
@backstage/plugin-kubernetes-backend npm | All versions | 0.21.8 |
Products include Linuxfoundation Backstage, Linuxfoundation Backstage\/Plugin-Kubernetes-Backend.
How do I fix CVE-2026-106563?
Upgrade @backstage/plugin-kubernetes-backend to 0.21.8 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-106563 being exploited?
There is no known exploitation of CVE-2026-106563 in the wild and no public exploit code.
Other vulnerabilities in Linuxfoundation Backstage
- CVE-2026-106501 Backstage: Sensitive information exposure in Scaffolder
- CVE-2026-106558 Backstage: Improper validation of TechDocs MkDocs configuration
- CVE-2026-88064 Backstage: Improper input validation in TechDocs MkDocs configuration
- CVE-2026-106459 Backstage: Improper input validation in Sentry scaffolder actions
- CVE-2026-106486 Backstage: Improper filesystem validation in Bitbucket pull-request scaffolder actions
Sources
Also known as GHSA-r9ph-3637-55px.