Bug 2431878 (CVE-2026-24046)

Summary: CVE-2026-24046 backstage/backend-defaults: backstage/plugin-scaffolder-backend: backstage/plugin-scaffolder-node: possible symlink path traversal in scaffolder actions
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: abarbaro, alizardo, jchui, jhe, ktsao, nboldt, psrna
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Backstage. A symlink-based path traversal issue can be exploited in multiple Scaffolder actions and archive extraction utilities during template execution via malicious symlinks. An attacker with access to create and execute Scaffolder templates can read sensitive files, delete arbitrary files or write files outside the intended workspace, resulting in unauthorized information disclosure or system compromise.
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Description OSIDB Bzimport 2026-01-21 23:01:19 UTC 
Backstage is an open framework for building developer portals. Multiple Scaffolder actions and archive extraction utilities were vulnerable to symlink-based path traversal attacks. An attacker with access to create and execute Scaffolder templates could exploit symlinks to read arbitrary files via the `debug:log` action by creating a symlink pointing to sensitive files (e.g., `/etc/passwd`, configuration files, secrets); delete arbitrary files via the `fs:delete` action by creating symlinks pointing outside the workspace, and write files outside the workspace via archive extraction (tar/zip) containing malicious symlinks. This affects any Backstage deployment where users can create or execute Scaffolder templates. This vulnerability is fixed in `@backstage/backend-defaults` versions 0.12.2, 0.13.2, 0.14.1, and 0.15.0; `@backstage/plugin-scaffolder-backend` versions 2.2.2, 3.0.2, and 3.1.1; and `@backstage/plugin-scaffolder-node` versions 0.11.2 and 0.12.3. Users should upgrade to these versions or later. Some workarounds are available. Follow the recommendation in the Backstage Threat Model to limit access to creating and updating templates, restrict who can create and execute Scaffolder templates using the permissions framework, audit existing templates for symlink usage, and/or run Backstage in a containerized environment with limited filesystem access.