Rubygem-foreman_remote_execution: command injection in job invocations via effective_user parameter

A flaw was found in rubygem-foreman_remote_execution. A command injection vulnerability exists in the Red Hat Satellite API (/api/v2/job_invocations). When a job template has the effective_user property marked as overridable: true, the application fails to properly sanitize the effective_user input provided during the API request. The exploitation does not rely on the content or logic of the Job Template/playbook itself; rather, the injection occurs during the instantiation of the job execution environment by the Satellite server. An attacker with permissions to execute job templates can inject arbitrary shell commands into this parameter, which are executed on the target infrastructure with the privileges of the execution user.