# CVE-2026-106504: Backstage scaffolder-backend sensitive information exposure in task logs

Source: https://junglewise.ai/threats/cve-2026-106504-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-2026-106504 · Severity: medium · CVSS 6.5 · Published 2026-10-06

Backstage is an open framework for building developer portals used to manage development infrastructure and workflows. The scaffolder backend component can expose sensitive values (such as credentials or API keys) in task logs when certain permission restrictions are in place. An authenticated user who can create and monitor scaffolder tasks may be able to view these sensitive values by exploiting denied actions that contain them in their inputs.

Technologies: [Backstage @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-2026-106504 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-106504 being exploited in the wild.

**How severe is CVE-2026-106504?** Medium severity, with a CVSS score of 6.5, published 6 October 2026.

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

**Is there a fix for CVE-2026-106504?** 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-2026-106504 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-106504?** Check whether you run Backstage @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 prior to version 4.1.0 does not properly redact sensitive input values from task logs when scaffolder actions are denied due to permission restrictions. An authenticated user with scaffolder task creation and viewing permissions can observe sensitive values in logs of denied actions in deployments with restrictive action permissions. The vulnerability requires the attacker to know or craft a denied action containing a sensitive value to trigger the information leak.

## Affected products

- Backstage @backstage/plugin-scaffolder-backend prior to 4.1.0

## Identifiers

- CVE-2026-106504
- GHSA-4xvq-3m68-h444

## Timeline

- 2026-10-06: disclosed
- 2026-08-27: patched: Fix commit merged

## References

- [https://github.com/backstage/backstage/commit/3eb3dc59eb0da0deccd532f19eb460bb452c9efb](https://github.com/backstage/backstage/commit/3eb3dc59eb0da0deccd532f19eb460bb452c9efb)
- [https://github.com/backstage/backstage/releases/tag/v1.54.6](https://github.com/backstage/backstage/releases/tag/v1.54.6)

## 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 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)
- [Backstage plugin-scaffolder-backend improper task state validation](https://junglewise.ai/threats/cve-2026-106500-backstage-is-an-open-framework-for-building-developer-portals)