CVE-2026-29184: @backstage/plugin-scaffolder-backend: Potential Session Token Exfiltration via Log Redaction Bypass
Impact
A malicious scaffolder template can bypass the log redaction mechanism to exfiltrate secrets provided run through task event logs.
The attack requires: - The ability to register a template in the catalog - A victim who executes the malicious template
Patches Patched in @backstage/plugin-scaffolder-backend version 3.1.4
Workarounds - Implement a custom permission policy that restricts scaffolder.task.read so users can only read their own task logs - Restrict who can register templates in the catalog to trusted users only
Resources - Backstage Scaffolder permissions documentation: https://backstage.io/docs/permissions/plugin-authors/01-setup/ - Backstage Threat Model: https://backstage.io/docs/overview/threat-model/
Other sources
Backstage is an open framework for building developer portals. Prior to version 3.1.4, a malicious scaffolder template can bypass the log redaction mechanism to exfiltrate secrets provided run through task event logs. This issue has been patched in version 3.1.4.
— MITRE
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-29184?
CVE-2026-29184 is considered a high severity vulnerability due to its ability to exfiltrate sensitive information from event logs.
How do I fix CVE-2026-29184?
To fix CVE-2026-29184, upgrade to @backstage/plugin-scaffolder-backend version 3.1.4 or later.
Who is affected by CVE-2026-29184?
CVE-2026-29184 affects users of the @backstage/plugin-scaffolder-backend version 3.1.3 or earlier.
What type of attack is possible with CVE-2026-29184?
CVE-2026-29184 allows a malicious scaffolder template to bypass log redaction and potentially exfiltrate secrets.
What are the prerequisites for exploiting CVE-2026-29184?
Exploitation of CVE-2026-29184 requires the ability to register a malicious template and for a user to execute it.