CVE-2026-47680
Fix: fluxcd/source-controller#2054CVE-2026-47680 is a security vulnerability in github.com/fluxcd/source-controller. O3 Security confirms whether CVE-2026-47680 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Source controller: Improper path handling allows traversal
Real-World Exposure
github.com/fluxcd/source-controllerReal-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
Impact
An actor with the ability to influence the contents of a bucket referenced by a Bucket resource can cause source-controller to write fetched object data to paths outside the per-reconciliation working directory.
The corruption surface is bounded by source-controller's own and downstream Flux controllers' digest verification: source-controller verifies stored artifact digests during reconciliation and rebuilds on divergence; consumers (kustomize-controller, helm-controller) verify the digest of fetched artifacts and reject mismatches. These checks prevent a manipulated artifact from reaching the cluster, but an attacker can still write files anywhere the source-controller pod has permission to write.
Separately, a user with permission to create or update GitRepository resources can cause source-controller to test for the existence of paths outside the cloned repository. Because the result is exposed via the resource's status, this allows limited enumeration of file paths on the controller pod. This surface exists only on source-controller v1.6.0 and later, where the sparse-checkout feature was introduced.
Patches
This vulnerability was fixed in source-controller v1.8.5.
Workarounds
There is no in-product workaround. Users should upgrade to a patched version.
As a defense-in-depth measure for the GitRepository sparse-checkout surface, a ValidatingAdmissionPolicy (or a third-party policy engine such as Kyverno or OPA Gatekeeper) can be deployed to reject GitRepository resources whose .spec.sparseCheckout entries contain .. or absolute path segments.
References
Credits
The path traversal in the Bucket reconciler was reported by JUNYI LIU. The path traversal in the GitRepository sparse-checkout validation was found and patched by the Flux engineering team.
For more information
If you have any questions or comments about this advisory:
- Open an issue in the source-controller repository.
- Contact us at the CNCF Flux Channel.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/fluxcd/source-controller | ≥ 0.0.17&&< 1.8.5 | 1.8.5 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/fluxcd/source-controller. 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/fluxcd/source-controller to 1.8.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-47680 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-2026-47680 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-2026-47680. 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-2026-47680 in your dependencies?
O3 detects CVE-2026-47680 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.