I could be wrong, but I don't believe we do CVE analysis for end of life versions. Both PE 2021.7.x (LTS) and 2023.x have had updates released to address this specific CVE. If 2019.8.x is affected, we would not port a fix to an unsupported release. I would say if you are using the orchestrator in 2019.8.x, you likely want to update as soon as you can, not just for the CVE, but to remain within what we can support.
https://www.puppet.com/security/cve/cve-2023-2530-remote-code-execution-orchestrator
Have you had any discussion with your account team on this yet?