CVE-2026-106459 backstage CVE debrief

Who should care

Defenders responsible for Backstage deployments should assess exposure and prioritize upgrading `@backstage/plugin-scaffolder-backend-module-sentry` to version `0.3.8` or later. This includes operators, platform teams, vulnerability management teams, and security teams who need to review affected scope, severity, and vendor guidance.

Why it matters

CVE-2026-106459 is an improper input validation vulnerability in the Sentry scaffolder actions of Backstage. Defenders should prioritize upgrading `@backstage/plugin-scaffolder-backend-module-sentry` to version `0.3.8` or later to prevent potential credential disclosure.

• Authenticated internal users may be able to disclose Sentry integration credentials.
• Subsequent impact depends on network reachability and the privileges granted to the configured token.

Technical summary

CVE-2026-106459 is an improper input validation vulnerability in the Sentry scaffolder actions of Backstage. An authenticated internal user who can execute the affected actions may cause the backend to contact unintended destinations and disclose Sentry integration credentials. The vulnerability is addressed by upgrading `@backstage/plugin-scaffolder-backend-module-sentry` to version `0.3.8` or later, which removes custom action-level `apiBaseUrl` values. Users should move any such value to `scaffolder.sentry.apiBaseUrl` before upgrading.

Defensive priority

Authenticated internal users may be able to cause the backend to contact unintended destinations and disclose Sentry integration credentials.

Recommended defensive actions

• Upgrade `@backstage/plugin-scaffolder-backend-module-sentry` to version `0.3.8` or later.
• Disable the affected actions until the patched package is deployed.
• Restrict `scaffolder.action.execute` permission for the affected Sentry actions to trusted users and templates.
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.
• 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 patches. The NVD entry is currently unavailable. Defenders should verify affected scope, review official advisories, and plan updates through normal change control. Compensating controls and monitoring should be reviewed for exposed systems. Exceptions and retesting are required for remediated assets.

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.