CVE-2026-40090 is a high-severity (CVSS 7.1) Path Traversal vulnerability in github.com/zarf-dev/zarf. O3 Security confirms whether CVE-2026-40090 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Zarf has a Path Traversal via Malicious Package Metadata.Name — Arbitrary File Write
Real-World Exposure
github.com/zarf-dev/zarfReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Zarf is an Airgap Native Packager Manager for Kubernetes. Versions 0.23.0 through 0.74.1 contain an arbitrary file write vulnerability in the zarf package inspect sbom and zarf package inspect documentation subcommands. These subcommands output file paths are constructed by joining a user-controlled output directory with the package's Metadata.Name field read directly from the untrusted package's zarf.yaml manifest. Although Metadata.Name is validated against a regex on package creation, an attacker can unarchive a package to modify the Metadata.Name field to contain path traversal sequences such as ../../etc/cron.d/malicious or absolute paths like /home/user/.ssh/authorized_keys, along with the corresponding files inside SBOMS.tar. This allows writing attacker-controlled content to arbitrary filesystem locations within the permissions of the user running the inspect command. This issue has been fixed in version 0.74.2.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/zarf-dev/zarf | ≥ 0.23.0&&< 0.74.2 | 0.74.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/zarf-dev/zarf. 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 github.com/zarf-dev/zarf to 0.74.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-40090 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-2026-40090 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-2026-40090. 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-2026-40090 in your dependencies?
O3 detects CVE-2026-40090 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.