Fork the dependency and use that, to have a stable non-changing base which you use. And additionally, make the original project a dependency but don't actually use it. This way you'll get CVE information from your tooling.
If you fork a dependency and change features, the CVE information on original depenency is now no longer valid for your code. Your additions or removals can induce new CVEs, or render CVE for original lib a moot point.
Fork the dependency and use that, to have a stable non-changing base which you use. And additionally, make the original project a dependency but don't actually use it. This way you'll get CVE information from your tooling.