CVE-2026-106499 backstage CVE debrief

Who should care

Backstage administrators and developers using Scaffolder templates with sensitive data should assess exposure and take remediation steps. This includes reviewing and updating Scaffolder templates, verifying access controls for task logs, and upgrading to the fixed version of the @backstage/plugin-scaffolder-backend package. Additionally, operators, platform administrators, and security teams should be aware of the potential impact on their environments and

Why it matters

A vulnerability in the @backstage/plugin-scaffolder-backend package could expose secret-derived values in Scaffolder task logs, affecting deployments with sensitive scaffolder.defaultEnvironment.secrets and allowing an attacker to create or modify Scaffolder templates.

• Potential exposure of sensitive data in task logs
• Need to review and update Scaffolder templates
• Verification of access controls for task logs
• Upgrade to fixed version of @backstage/plugin-scaffolder-backend

Technical summary

The @backstage/plugin-scaffolder-backend package could expose secret-derived values in Scaffolder task logs due to a vulnerability. This issue arises from the package's handling of sensitive data during template iteration, potentially leading to the persistence and exposure of secret-derived values in task logs. The vulnerability is fixed in version 4.1.0. Users should assess their deployments, review Scaffolder templates, and implement compensating controls as necessary to mitigate the risk of sensitive data exposure.

Defensive priority

Medium priority for Backstage deployments using Scaffolder templates with sensitive data

Recommended defensive actions

• Review and update Scaffolder templates to prevent exposure of sensitive data
• Verify and restrict access to task logs for sensitive information
• Upgrade to version 4.1.0 or later of the @backstage/plugin-scaffolder-backend package
• Conduct a thorough review of affected deployments and assign ownership for follow-up
• 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
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed

Evidence notes

The CVE record and source item provide details on the vulnerability, but additional information on affected versions and remediation is limited. The @backstage/plugin-scaffolder-backend package's handling of secret-derived values in Scaffolder task logs is a critical aspect to consider. Users should verify the exposure of sensitive data and review Scaffolder templates for potential vulnerabilities. The source references provided offer additional context for understanding the issue and implementing mitigations.

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.