CVE-2026-106504: Sensitive Information Exposure in @backstage/plugin-scaffolder-backend Task Logs
Summary
CVE-2026-106504: Backstage has sensitive information exposure in scaffolder task logs. Affects @backstage/plugin-scaffolder-backend versions < 4.1.0. Fixed in 4.1.0. How to fix ↓
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Background
The @backstage/plugin-scaffolder-backend package is a crucial component of the Backstage platform, which facilitates the creation and management of software components. It allows users to scaffold new projects and manage templates efficiently. However, this package has a vulnerability that can expose sensitive information through task logs, particularly in environments where action permissions are tightly controlled.
Vulnerability Detail
The vulnerability arises from the way scaffolder task logs handle sensitive values. An authenticated user with the ability to create and read scaffolder tasks may inadvertently access sensitive information if a task is denied due to restrictive action permissions. This exposure can lead to unauthorized access to sensitive data, potentially compromising the security of the application and its users.
How To Fix
Latest published version: 4.2.1 as of 22 Oct 2026
npm install @backstage/plugin-scaffolder-backend@4.2.1Upgrading to it may include breaking changes; the version below is the minimum fixed release for this vulnerability.
If you need the minimum change
4.1.0
This is the first release that contains the fix.
npm install @backstage/plugin-scaffolder-backend@4.1.0Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary measure, restrict the creation of scaffolder tasks and the reading of task logs to trusted users only. Additionally, avoid using centrally managed sensitive values in inputs to actions that may be denied until you can upgrade to the patched version.
Conclusion
In summary, CVE-2026-106504 poses a significant risk of sensitive information exposure in the @backstage/plugin-scaffolder-backend package. It is crucial to update to version 4.1.0 or later to mitigate this risk. Implementing the recommended workarounds can provide temporary relief until an upgrade is possible.
See every vulnerability recorded for @backstage/plugin-scaffolder-backend →
FAQ
CVE-2026-106504 is a vulnerability in the @backstage/plugin-scaffolder-backend package that allows authenticated users to access sensitive information through task logs.
You can check if your application is affected by using the Vulert playground at Vulert Scanner, which monitors vulnerabilities using your package-lock.json file.
The main risk is unauthorized access to sensitive data, which could lead to data breaches and compromise the security of your application.
If you cannot upgrade immediately, implement the suggested workarounds by restricting access to scaffolder tasks and avoiding sensitive values in inputs.
The CVSS score for this vulnerability is 6.5, indicating a moderate level of severity.
References
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