A DMZ (demilitarised zone) is a perimeter network that enables organisations to protect their internal networks. It enables organisations to provide access to untrusted networks, such as the internet while keeping private networks / local-area networks (LANs) secure. In essence, a DMZ acts as a buffer between the internet and private networks.
Whilst it can be used as an additional layer of protection from risks posed by your organisation’s external-facing infrastructure/services, a DMZ network by itself is not secure, as it's exposed to the internet.
If you are using a DMZ, it should only host external-facing services and there should be no sensitive data stored within this zone. However, this is not enough to mitigate the flagged vulnerabilities and you will need to take further action.