CVE-2026-24046 is a high-severity (CVSS 7.1) Path Traversal vulnerability in @backstage/backend-defaults. A fix is available for @backstage/backend-defaults — see the affected versions and patch details below.
Backstage has a Possible Symlink Path Traversal in Scaffolder Actions
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-24046.
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.
How urgent is this, really
CVE-2026-24046 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 379,145 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
@backstage/backend-defaultsnpmDescription
Impact
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:logaction by creating a symlink pointing to sensitive files (e.g.,/etc/passwd, configuration files, secrets) - Delete arbitrary files via the
fs:deleteaction by creating symlinks pointing outside the workspace - 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.
Patches
This vulnerability is fixed in the following package versions:
@backstage/backend-defaultsversion 0.12.2, 0.13.2, 0.14.1, 0.15.0@backstage/plugin-scaffolder-backendversion 2.2.2, 3.0.2, 3.1.1@backstage/plugin-scaffolder-nodeversion 0.11.2, 0.12.3
Users should upgrade to these versions or later.
Workarounds
- 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
- Run Backstage in a containerized environment with limited filesystem access
References
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @backstage/backend-defaults | all versions | 0.12.2npm install @backstage/backend-defaults@0.12.2 |
| 📦npm | @backstage/backend-defaults | ≥ 0.13.0&&< 0.13.2 | 0.13.2npm install @backstage/backend-defaults@0.13.2 |
| 📦npm | @backstage/backend-defaults | ≥ 0.14.0&&< 0.14.1 | 0.14.1npm install @backstage/backend-defaults@0.14.1 |
| 📦npm | @backstage/plugin-scaffolder-backend | all versions | 2.2.2npm install @backstage/plugin-scaffolder-backend@2.2.2 |
| 📦npm | @backstage/plugin-scaffolder-backend | ≥ 3.0.0&&< 3.0.2 | 3.0.2npm install @backstage/plugin-scaffolder-backend@3.0.2 |
| 📦npm | @backstage/plugin-scaffolder-backend | ≥ 3.1.0&&< 3.1.1 | 3.1.1npm install @backstage/plugin-scaffolder-backend@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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-24046 can be triaged on real exposure rather than presence alone.
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.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
To exploit this issue, an attacker needs to have access to create and execute Scaffolder actions, specifically the debug:log, fs:delete actions and archive extractions, limiting the exposure of this flaw. Additionally, file systems operations are constrained by the permissions of the process, limiting the impact to…
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Developer Hub 1.8 | rhdh/rhdh-hub-rhel9:1774545605 | RHSA-2026:6174 |
| Red Hat Developer Hub 1.9 | rhdh/rhdh-hub-rhel9:1775140647 | RHSA-2026:6802 |
Frequently Asked Questions
Is CVE-2026-24046 in your dependencies?
O3 Security finds CVE-2026-24046 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.