The primary purpose of the CVE system is to uniquely identify vulnerabilities. Each CVE entry provides a unique identifier for a single cybersecurity vulnerability, ensuring consistent reference and discussion across different platforms. 'Cataloging virus entities' is incorrect because CVE does not catalog viruses or malware but vulnerabilities. 'Classifying virtual ecosystem threats' inaccurately narrows the scope of CVE to virtual ecosystems, while CVE applies to a broader range of cybersecurity concerns. 'Creating vulnerability exploits' is not the goal of CVE; rather, CVE aims to document the vulnerabilities that could potentially be exploited.