CVE-2026-106563: @backstage Plugin-Kubernetes-Backend

Medium severity, CVSS 5.3. EPSS: 0.2% chance of exploitation in the next 30 days.

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.

Affected products

• @backstage Plugin-Kubernetes-Backend: before 0.21.8 (fixed in 0.21.8)
• Backstage Backstage: before 1.54.1 (fixed in 1.54.1)

Published 2026-10-07. Last modified 2026-10-10.