Artifact Hub allows unsafe rego built-in

Artifact Hub is a web-based application that enables finding, installing, and publishing packages and configurations for CNCF projects. During a security audit of Artifact Hub's code base a security researcher identified a bug in which a default unsafe rego built-in was allowed to be used when defining authorization policies. Artifact Hub includes a fine-grained authorization mechanism that allows organizations to define what actions can be performed by their members. It is based on customizable authorization policies that are enforced by the `Open Policy Agent`. Policies are written using `rego` and their data files are expected to be json documents. By default, `rego` allows policies to make HTTP requests, which can be abused to send requests to internal resources and forward the responses to an external entity. In the context of Artifact Hub, this capability should have been disabled. This issue has been resolved in version `1.16.0`. Users are advised to upgrade. There are no known workarounds for this vulnerability.