CVE-2026-106486: Improper Filesystem Validation in Backstage Bitbucket Scaffolder Actions
Summary
CVE-2026-106486: Backstage has iImproper filesystem validation in Bitbucket pull-request scaffolder actions. Affects @backstage/plugin-scaffolder-backend-module-bitbucket-cloud versions < 0.3.10. Fixed in 0.3.10. How to fix ↓
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Background
Backstage is an open platform for building developer portals, allowing teams to manage their software infrastructure. The Bitbucket scaffolder actions within Backstage enable users to create new projects and repositories based on templates. However, a vulnerability has been identified that allows authenticated users to manipulate filesystem paths, potentially leading to unauthorized access to sensitive data.
Vulnerability Detail
The vulnerability arises from improper filesystem validation in the Bitbucket pull-request scaffolder actions. An authenticated user can execute a template and influence an allowed Bitbucket repository, which may lead to filesystem paths being affected outside the expected working area. This could compromise the confidentiality, integrity, or availability of the backend, depending on the deployment configuration.
How To Fix
Latest published version: 0.3.12 as of 23 Oct 2026
npm install @backstage/plugin-scaffolder-backend-module-bitbucket-cloud@0.3.12Upgrading to it may include breaking changes; the version below is the minimum fixed release for this vulnerability.
If you need the minimum change
0.3.10
This is the first release that contains the fix.
npm install @backstage/plugin-scaffolder-backend-module-bitbucket-cloud@0.3.10Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
Restrict the execution of affected Scaffolder templates to trusted users and avoid using templates that accept user-controlled target repositories for these actions.
Conclusion
The CVE-2026-106486 vulnerability in Backstage's Bitbucket scaffolder actions poses a significant risk due to improper filesystem validation. It is crucial for users to update to the patched versions of the affected packages and implement the recommended workarounds to mitigate potential risks.
See every vulnerability recorded for @backstage/plugin-scaffolder-backend-module-bitbucket-cloud →
FAQ
CVE-2026-106486 is a vulnerability in Backstage that allows improper filesystem validation in Bitbucket scaffolder actions, potentially leading to unauthorized access to sensitive data.
Authenticated users who can execute templates in Backstage and influence Bitbucket repositories are affected by this vulnerability.
The vulnerability can compromise backend confidentiality, integrity, or availability, depending on the deployment setup.
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The CVSS score of this vulnerability is 8.5, indicating a high severity level.
