CVE-2022-39272

Flux is an open and extensible continuous delivery solution for Kubernetes. Versions prior to 0.35.0 are subject to a Denial of Service. 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. This issue is patched in version 0.35.0. As a workaround, 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.

Flux is an open and extensible continuous delivery solution for Kubernetes. Versions prior to 0.35.0 are subject to a Denial of Service. 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. This issue is patched in version 0.35.0. As a workaround, 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.

Flux controllers 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 is not fully compatible with the Go type time.Duration as explained in https://github.com/kubernetes/apimachinery/issues/131, and b) a lack of validation within Flux to restrict allowed values.

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](https://github.com/kubernetes/apimachinery/issues/131); 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](https://fluxcd.io/security/#report-a-vulnerability)). ### 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 - https://github.com/kubernetes/apimachinery/issues/131

Flux es una solución de entrega continua abierta y extensible para Kubernetes. Las versiones anteriores a 0.35.0, están sujetas a una denegación de servicio. Los usuarios que presentan permisos para cambiar los objetos de Flux, ya sea medainyte una fuente de Flux o directamente dentro de un clúster, pueden proporcionar datos no válidos a los campos ".spec.interval" o ".spec.timeout" (y variaciones estructuradas de estos campos), causando que todo el tipo de objeto deje de ser procesado. Este problema ha sido corregido en versión 0.35.0. Como mitigación, pueden emplearse controladores de admisión para restringir los valores que pueden usarse para los campos ".spec.interval" y ".spec.timeout", aunque la actualización a las últimas versiones sigue siendo la mitigación recomendada