CVE-2026-106501 in Backstage
Summary
by MITRE • 10/07/2026
Backstage is an open framework for building developer portals. Prior to 3.3.1, 3.4.1, 4.0.3 and 4.1.0, the @backstage/plugin-scaffolder-backend package is affected by sensitive information exposure in scaffolder. An authenticated Backstage user who can read another user's Scaffolder task may receive internal execution data. In deployments where that data contains credentials for an external service, this may permit disclosure and unauthorized changes in that external service. This issue is fixed in versions 3.3.1, 3.4.1, 4.0.3 and 4.1.0.
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Analysis
by VulDB Data Team • 10/07/2026
The Backstage developer portal framework contains a critical information disclosure vulnerability within the @backstage/plugin-scaffolder-backend package that affects multiple release branches prior to versions 3.3.1, 3.4.1, 4.0.3, and 4.1.0. This flaw stems from an improper restriction of sensitive data exposure during the execution of scaffolding tasks. Scaffolding in Backstage is a process used to generate new projects or services based on predefined templates, often involving complex backend operations that may require authentication credentials for external systems such as cloud providers, databases, or API gateways. The vulnerability allows any authenticated user who possesses read access to another user's scaffolder task to retrieve internal execution data associated with that task. This design flaw bypasses the intended isolation between users and tasks, effectively exposing sensitive operational details that should remain confidential within the backend infrastructure.
From a technical perspective, this issue is classified under CWE-200: Information Exposure as it involves the leakage of system-specific information to an unauthorized actor. The vulnerability specifically targets the scaffolder plugin's API endpoints or data structures which return task execution logs and configuration details without sufficient validation of whether the requesting user has permission to view sensitive fields within those payloads. In many enterprise deployments, these internal execution contexts include service account tokens, private keys, or connection strings required for the scaffolding process to interact with external services. By accessing this data, an attacker can extract credentials that were intended solely for backend automation purposes rather than end-user consumption. This represents a significant breach of confidentiality and trust within the developer portal environment.
The operational impact of this vulnerability is severe due to its potential for lateral movement and unauthorized access to critical infrastructure. If the exposed internal execution data contains valid credentials for an external service, such as AWS IAM keys or Kubernetes cluster tokens, an attacker can leverage these secrets to perform actions outside the scope of their Backstage permissions. This could lead to unauthorized changes in those external services, including provisioning resources, modifying configurations, or exfiltrating data from connected systems. The attack path is relatively straightforward for any authenticated user with read access to scaffolder tasks, lowering the barrier for exploitation and increasing the risk surface significantly within organizations that rely heavily on Backstage for their software development lifecycle automation.
To mitigate this vulnerability, organizations must immediately upgrade the @backstage/plugin-scaffolder-backend package to version 3.3.1, 3.4.1, 4.0.3, or 4.1.0 depending on their current release track. These versions contain patches that enforce stricter access controls and sanitize sensitive fields from task execution responses returned to the frontend. Additionally, administrators should audit existing scaffolder templates to ensure they do not unnecessarily expose high-privilege credentials in logs or output variables accessible via the UI. Implementing robust role-based access control policies within Backstage can further limit which users have read access to other users' tasks, thereby reducing the attack surface even before patching is fully deployed. Regular security assessments of developer portal configurations are recommended to prevent similar information disclosure issues in related plugins and services aligned with ATT&CK techniques involving credential harvesting from local system databases or application logs.