CVE-2026-106563
Backstage: Improper entity validation in deprecated Kubernetes services endpoint
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Backstage: Improper entity validation in deprecated Kubernetes services endpoint
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.
- Record
CVE-2026-106563- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-20, CWE-862
- Updated
- 2026-11-02
EUVDEUVD-2026-94376
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.
- Record
EUVD-2026-94376- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-r9ph-3637-55px
Backstage: Improper entity validation in deprecated Kubernetes services endpoint
Impact
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.
Patches
Patched in @backstage/plugin-kubernetes-backend version 0.21.8.
Workarounds
- Disable the deprecated
/services/:serviceIdroute by deploying a custom Kubernetes router that omits it. - Restrict access to the
kubernetes.resources.readpermission to limit the set of users who can reach the endpoint.
- Record
GHSA-r9ph-3637-55px- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-20, CWE-862
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2026-106563- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N - CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-20, CWE-862
- Updated
- 2026-11-02
OSV
Backstage: Improper entity validation in deprecated Kubernetes services endpoint
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.
- Record
CVE-2026-106563- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-20, CWE-862
- Updated
- 2026-11-02
OSVGHSA-r9ph-3637-55px
Backstage: Improper entity validation in deprecated Kubernetes services endpoint
Impact
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.
Patches
Patched in @backstage/plugin-kubernetes-backend version 0.21.8.
Workarounds
- Disable the deprecated
/services/:serviceIdroute by deploying a custom Kubernetes router that omits it. - Restrict access to the
kubernetes.resources.readpermission to limit the set of users who can reach the endpoint.
- Record
GHSA-r9ph-3637-55px- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-20, CWE-862
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
@backstage/plugin-kubernetes-backendnpm |
before 0.21.8 | 0.21.8 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-106563 is a medium vulnerability (CVSS 5.3) in @backstage Plugin-kubernetes-backend, published October 7, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.22%, the 13th percentile. Fixed in @backstage/plugin-kubernetes-backend 0.21.8.
References
github.com/backstage/backstage/security/advisories/GHSA-r9ph-3637-55px
nvd.nist.gov/vuln/detail/CVE-2026-106563