GHSA-f4p5-x4vc-mh4v
MEDIUMImproper use of metav1.Duration allows for Denial of Service
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
github.com/fluxcd/flux2🐹github.com/fluxcd/source-controller🐹github.com/fluxcd/kustomize-controller🐹github.com/fluxcd/helm-controller🐹github.com/fluxcd/notification-controller🐹github.com/fluxcd/image-automation-controller🐹github.com/fluxcd/image-reflector-controller🐹github.com/fluxcd/helm-controller/api+5 moreReal-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
Flux controllers within the affected versions range are vulnerable to a denial of service attack. Users that have permissions to change Flux’s objects, either through a Flux source or directly within a cluster, can provide invalid data to fields .spec.interval or .spec.timeout (and structured variations of these fields), causing the entire object type to stop being processed.
The issue has two root causes: a) the Kubernetes type metav1.Duration not being fully compatible with the Go type time.Duration as explained on upstream report; b) lack of validation within Flux to restrict allowed values.
Workarounds
Admission controllers can be employed to restrict the values that can be used for fields .spec.interval and .spec.timeout, however upgrading to the latest versions is still the recommended mitigation.
Credits
This issue was reported by Alexander Block (@codablock) through the Flux security mailing list (as recommended).
For more information
If you have any questions or comments about this advisory:
- Open an issue in any of the affected repositories.
- Contact us at the CNCF Flux channel.
References
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/fluxcd/flux2 | ≥ 0.1.0&&< 0.35.0 | 0.35.0 |
| 🐹Go | github.com/fluxcd/source-controller | ≥ 0.0.1-alpha-1&&< 0.30.0 | 0.30.0 |
| 🐹Go | github.com/fluxcd/kustomize-controller | ≥ 0.0.1-alpha-1&&< 0.29.0 | 0.29.0 |
| 🐹Go | github.com/fluxcd/helm-controller | ≥ 0.0.1-alpha-1&&< 0.24.0 | 0.24.0 |
| 🐹Go | github.com/fluxcd/notification-controller | ≥ 0.0.1-alpha-1&&< 0.27.0 | 0.27.0 |
| 🐹Go | github.com/fluxcd/image-automation-controller | ≥ 0.1.0&&< 0.26.0 | 0.26.0 |
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/flux2. 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/flux2 to 0.35.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-f4p5-x4vc-mh4v 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 GHSA-f4p5-x4vc-mh4v 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 GHSA-f4p5-x4vc-mh4v. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-f4p5-x4vc-mh4v in your dependencies?
O3 detects GHSA-f4p5-x4vc-mh4v across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.