How can I find the list of applications affected by a vulnerability?

You can find the set of applications affected by a particular vulnerability in Nexus IQ Server by using the Advanced Search feature (https://help.sonatype.com/en/advanced-search.html).

Search for a vulnerability using the following term:

vulnerabilityId:<CVE>

E.g.

vulnerabilityId:CVE-2020-28052

And this will return all applications that are affected by it.

There is also an Advanced Search REST API available
https://help.sonatype.com/en/advanced-search-rest-api.html