CVE-2026-24046
HIGHBackstage has a Possible Symlink Path Traversal in Scaffolder Actions
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
@backstage/backend-defaultsnpmDescription
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @backstage/backend-defaults | all versions | 0.12.2 |
| 📦npm | @backstage/backend-defaults | ≥ 0.13.0&&< 0.13.2 | 0.13.2 |
| 📦npm | @backstage/backend-defaults | ≥ 0.14.0&&< 0.14.1 | 0.14.1 |
| 📦npm | @backstage/plugin-scaffolder-backend | all versions | 2.2.2 |
| 📦npm | @backstage/plugin-scaffolder-backend | ≥ 3.0.0&&< 3.0.2 | 3.0.2 |
| 📦npm | @backstage/plugin-scaffolder-backend | ≥ 3.1.0&&< 3.1.1 | 3.1.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @backstage/backend-defaults. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update @backstage/backend-defaults to 0.12.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-24046 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-24046 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-24046. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-24046 in your dependencies?
O3 detects CVE-2026-24046 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.