CVE-2026-106502 backstage CVE debrief

Who should care

Defenders responsible for Backstage deployments, especially those using `@backstage/plugin-scaffolder-backend` versions prior to 4.1.0, should assess their exposure and take necessary actions to restrict Scaffolder template execution and task-event access to trusted users.

Why it matters

CVE-2026-106502 is a vulnerability in `@backstage/plugin-scaffolder-backend` that may allow authenticated users to retrieve sensitive values from Scaffolder task events under specific conditions. Defenders should prioritize verifying exposure and restricting access to trusted users.

• Potential exposure of backend-managed credentials used during task execution.
• Need to verify exposure in Backstage deployments using `@backstage/plugin-scaffolder-backend` versions prior to 4.1.0.
• Requirement to restrict Scaffolder template execution and task-event access to trusted users.

Technical summary

The vulnerability exists in `@backstage/plugin-scaffolder-backend` versions prior to 4.1.0. Under specific template and failure conditions, an authenticated user may be able to retrieve sensitive values from Scaffolder task events, potentially exposing backend-managed credentials used during task execution. This issue is patched in `@backstage/plugin-scaffolder-backend` version 4.1.0. Defenders should prioritize verifying exposure in their Backstage deployments, especially those using `@backstage/plugin-scaffolder-backend` versions prior to 4.1.0, and restrict Scaffolder template execution and task-event access to trusted users.

Defensive priority

Defenders should prioritize verifying exposure in their Backstage deployments, especially those using `@backstage/plugin-scaffolder-backend` versions prior to 4.1.0, and restrict Scaffolder template execution and task-event access to trusted users.

Recommended defensive actions

• Verify the version of `@backstage/plugin-scaffolder-backend` in use and upgrade to version 4.1.0 or later if necessary.
• Restrict Scaffolder template execution and task-event access to trusted users until the patched version is deployed.
• Monitor Scaffolder task events for potential exposure of sensitive information.
• 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.
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.

Evidence notes

The source corpus indicates that under specific template and failure conditions, an authenticated user may be able to retrieve sensitive values from Scaffolder task events, potentially exposing backend-managed credentials used during task execution. This issue is patched in `@backstage/plugin-scaffolder-backend` version 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.