Backstage's scaffolder credential handling may allow unintended GitHub authentication fallbackGHSA-29gx-h2m3-xw44
MEDIUMFix: backstage/backstage@6fb2a41GHSA-29gx-h2m3-xw44 is a medium-severity (CVSS 6.4) CWE-441 vulnerability in @backstage/plugin-scaffolder-backend. A fix is available for @backstage/plugin-scaffolder-backend — see the affected versions and patch details below.
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-29gx-h2m3-xw44.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
GHSA-29gx-h2m3-xw44 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 394,803 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
@backstage/plugin-scaffolder-backendnpm@backstage/plugin-scaffolder-backend-module-githubnpm@backstage/plugin-scaffolder-backend-module-gitlabnpmDescription
Impact
Scaffolder actions that interact with source control systems may not consistently enforce the intended credential boundaries under certain configurations. An authenticated user could perform operations with broader access than intended.
Patches
@backstage/plugin-scaffolder-backendversion4.1.0@backstage/plugin-scaffolder-backend-module-azureversion0.2.25@backstage/plugin-scaffolder-backend-module-bitbucket-cloudversion0.3.10@backstage/plugin-scaffolder-backend-module-bitbucket-serverversion0.2.25@backstage/plugin-scaffolder-backend-module-githubversion0.9.13@backstage/plugin-scaffolder-backend-module-gitlabversion0.11.10
The fix introduces a new configuration option that enforces user-provided credentials for supported SCM actions. The new behavior is opt-in for compatibility. After upgrading, set:
scaffolder:
requireScmUserCredentials: true
Before enabling this setting, review and update your templates as described in the software templates documentation referred to below.
Workarounds
If you cannot upgrade and enable the setting immediately:
- Restrict who can create Scaffolder tasks and which templates they can execute.
- Limit SCM integration credentials to the minimum repository read and mutation permissions required.
- Remove integration credentials for SCM hosts where all required operations can use explicitly supplied user tokens.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @backstage/plugin-scaffolder-backend | all versions | 4.1.0npm install @backstage/plugin-scaffolder-backend@4.1.0 |
| 📦npm | @backstage/plugin-scaffolder-backend-module-github | all versions | 0.9.13npm install @backstage/plugin-scaffolder-backend-module-github@0.9.13 |
| 📦npm | @backstage/plugin-scaffolder-backend-module-gitlab | all versions | 0.11.10npm install @backstage/plugin-scaffolder-backend-module-gitlab@0.11.10 |
| 📦npm | @backstage/plugin-scaffolder-backend-module-azure | all versions | 0.2.25npm install @backstage/plugin-scaffolder-backend-module-azure@0.2.25 |
| 📦npm | @backstage/plugin-scaffolder-backend-module-bitbucket-cloud | all versions | 0.3.10npm install @backstage/plugin-scaffolder-backend-module-bitbucket-cloud@0.3.10 |
| 📦npm | @backstage/plugin-scaffolder-backend-module-bitbucket-server | all versions | 0.2.25npm install @backstage/plugin-scaffolder-backend-module-bitbucket-server@0.2.25 |
Affected Products
backstagelinuxfoundationbackstage\/plugin-scaffolder-backendlinuxfoundationbackstage\/plugin-scaffolder-backend-module-azurelinuxfoundationbackstage\/plugin-scaffolder-backend-module-bitbucket-cloudlinuxfoundationbackstage\/plugin-scaffolder-backend-module-bitbucket-serverlinuxfoundationbackstage\/plugin-scaffolder-backend-module-githublinuxfoundationDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @backstage/plugin-scaffolder-backend, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @backstage/plugin-scaffolder-backend to 4.1.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-29gx-h2m3-xw44 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Red Hat rates this vulnerability as Moderate because exploitation requires authenticated access to developer portal instances configured with source-control management workflows, limiting exposure to registered users. Within Red Hat Developer Hub and Ansible Automation Platform deployments, improper boundary…
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.Source: Red Hat security advisory for GHSA-29gx-h2m3-xw44 (CC BY 4.0)
Frequently Asked Questions
Is GHSA-29gx-h2m3-xw44 in your dependencies?
Find it across npm, including transitive dependencies.