Source controller: Improper path handling allows traversal
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 1.8.5
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: no
- Technical impact: partial
Summary
The source-controller is a Kubernetes operator, specialised in artifacts acquisition from external sources such as Git, OCI, Helm repositories and S3-compatible buckets. In versions 0.0.17 through 1.8.4, 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. This vulnerability was fixed in source-controller v1.8.5. 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.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: partial
- Record last updated
Affected versions
- fluxcd source-controller
From 0.0.17 · fixed in 1.8.5
- github.com/fluxcd/source-controllerGo
From 0.0.17 · fixed in 1.8.5