CVE-2026-27111: Kargo has Missing Authorization Vulnerabilities in Approval & Promotion REST API Endpoints

Kargo’s authorization model includes a promote verb – a non-standard Kubernetes “dolphin verb” – that gates the ability to advance Freight through a promotion pipeline. This verb exists to separate the ability to manage promotion-related resources from the ability to trigger promotions, enabling fine-grained access control over what is often a sensitive operation.

The promote verb is correctly enforced in Kargo’s legacy gRPC API. However, three endpoints in the newer REST API omit this check, relying only on standard Kubernetes RBAC for the underlying resource operations (patch on freights/status or create on promotions). This permits users who hold those standard permissions – but who were deliberately not granted promote – to bypass the intended authorization boundary.

The affected endpoints are:

1. POST /v1beta1/projects/{project}/freight/{freight}/approve

Approves Freight for promotion to a specific Stage.

The endpoint is intended to require both patch permission on Freight status and promote permission on the target Stage, but asserts only the former.

2. POST /v1beta1/projects/{project}/stages/{stage}/promotions

Promotes Freight to a specific Stage.

The endpoint is intended to require both create permission on Promotion resources and promote permission on the target Stage, but asserts only the former.

3. POST /v1beta1/projects/{project}/stages/{stage}/promotions/downstream

Promotes Freight to all Stages immediately downstream of a given Stage.

The endpoint is intended to require both create permission on Promotion resources and promote permission on each downstream Stage, but asserts only the former.