# CVE-2026-106500: Backstage plugin-scaffolder-backend improper task state validation

Source: https://junglewise.ai/threats/cve-2026-106500-backstage-is-an-open-framework-for-building-developer-portals  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-06. Updated: 2026-10-06  
License: CC BY 4.0 with a link back

CVE-2026-106500 · Severity: high · CVSS 8.5 · Published 2026-10-06

Backstage is an open framework for building developer portals that teams use to manage internal development infrastructure. A flaw in the scaffolder backend allows authenticated users to manipulate task state during retries, potentially enabling them to read, modify, or delete files that the backend application can access. If the backend runs with write permissions to sensitive application files, an attacker could compromise the confidentiality, integrity, or availability of the entire Backstage deployment.

Technologies: [Backstage Plugin-Scaffolder-Backend](https://junglewise.ai/threats/technologies/plugin-scaffolder-backend), [@backstage/plugin-scaffolder-backend (npm)](https://junglewise.ai/threats/technologies/backstage-plugin-scaffolder-backend). Vendors: [Backstage](https://junglewise.ai/threats/vendors/backstage), [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2026-106500 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-106500 being exploited in the wild.

**How severe is CVE-2026-106500?** High severity, with a CVSS score of 8.5, published 6 October 2026.

**Which products and versions are affected?** Backstage Plugin-Scaffolder-Backend before 3.3.1, 3.4.1, 4.0.3, and 4.1.0; @backstage/plugin-scaffolder-backend (npm) < 4.1.0, SEMVER:introduced=0,fixed=4.1.0.

**Is there a fix for CVE-2026-106500?** Yes. @backstage/plugin-scaffolder-backend (npm): upgrade to 4.1.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-106500 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-106500?** Check whether you run Backstage Plugin-Scaffolder-Backend or @backstage/plugin-scaffolder-backend (npm) 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-scaffolder-backend (npm): upgrade to 4.1.0 or later

  ```sh
  npm install @backstage/plugin-scaffolder-backend@4.1.0
  ```


## Technical details

The @backstage/plugin-scaffolder-backend package fails to properly validate task state transitions during retry operations, allowing authenticated users with Scaffolder task creation permissions to retrigger tasks outside of terminal states under specific timing and deployment conditions. This improper state validation enables file system access violations that could affect any files writable by the backend process. The fix restricts task retries to terminal states only.

## Affected products

- Backstage plugin-scaffolder-backend before 3.3.1, 3.4.1, 4.0.3, and 4.1.0

## Identifiers

- CVE-2026-106500
- GHSA-xvgh-hmx8-9xxf

## Timeline

- 2026-10-06: disclosed
- 2026-08-28: patched

## References

- [https://github.com/backstage/backstage/commit/0d24f1b8701f3dde6cd597f81997c1ea873a43ae](https://github.com/backstage/backstage/commit/0d24f1b8701f3dde6cd597f81997c1ea873a43ae)
- [https://github.com/backstage/backstage/commit/56be299dd3ef6706e13e76ea2f8a9b0dd0b6413d](https://github.com/backstage/backstage/commit/56be299dd3ef6706e13e76ea2f8a9b0dd0b6413d)

## Related threats

- [Backstage scaffolder task list input validation vulnerability](https://junglewise.ai/threats/cve-2026-106506-backstage-is-an-open-framework-for-building-developer-portals)
- [Backstage scaffolder-backend sensitive information exposure in task logs](https://junglewise.ai/threats/cve-2026-106504-backstage-is-an-open-framework-for-building-developer-portals)
- [Backstage Scaffolder Backend authorization bypass in action input validation](https://junglewise.ai/threats/cve-2026-106503-backstage-is-an-open-framework-for-building-developer-portals)
- [Backstage plugin-scaffolder-backend credential exposure in task events](https://junglewise.ai/threats/cve-2026-106502-backstage-is-an-open-framework-for-building-developer-portals)
- [Backstage plugin-scaffolder-backend sensitive information exposure](https://junglewise.ai/threats/cve-2026-106501-backstage-is-an-open-framework-for-building-developer-portals)