CVE-2026-106501 backstage CVE debrief

Who should care

Defenders and administrators of Backstage deployments using affected versions of plugin-scaffolder-backend should assess exposure and apply mitigations to restrict access to Scaffolder tasks and protect external service credentials. They should prioritize verifying exposure, especially where external service credentials are used, and apply patches or mitigations. Security teams and vulnerability management teams should also review the vulnerability and its

Why it matters

CVE-2026-106501 is a critical vulnerability in Backstage's plugin-scaffolder-backend package. An authenticated user can access internal execution data of another user's Scaffolder task, potentially disclosing credentials for external services. Defenders should prioritize verifying exposure, especially where external service credentials are used, and apply patches or mitigations.

• Potential disclosure of external service credentials
• Unauthorized changes in external services
• Increased risk for lateral movement
• Need for verification of exposure and patching

Technical summary

The @backstage/plugin-scaffolder-backend package is vulnerable to sensitive information exposure in Scaffolder. An authenticated Backstage user who can read another user's Scaffolder task may receive internal execution data, potentially disclosing credentials for external services. This issue affects deployments using versions prior to 3.3.1, 3.4.1, 4.0.3, and 4.1.0. The vulnerability allows an authenticated user to access internal execution data of another user's Scaffolder task, potentially leading to unauthorized changes in external services.

Defensive priority

Defenders should prioritize verifying exposure in their deployments, especially where external service credentials are used, and apply patches or mitigations.

Recommended defensive actions

• Verify exposure in deployments using affected versions of plugin-scaffolder-backend
• Apply patches or mitigations to restrict access to Scaffolder tasks
• Monitor for unauthorized changes in external services
• Inventory and update affected versions to 3.3.1, 3.4.1, 4.0.3, or 4.1.0
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE record and source item provide details on the vulnerability and affected versions. However, specific exploitation instances or victim information are not provided. Defenders should verify exposure in their deployments, especially where external service credentials are used, and apply patches or mitigations. The @backstage/plugin-scaffolder-backend package is vulnerable to sensitive information exposure in Scaffolder. The issue is fixed in versions 3.3.1, 3.4.1, 4.0.3, and 4.1.0.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.