how to resolve a malware threat on CDN link

If it is an Avast warning about your website you'll need to reach out to Avast to find out why they have classified it that way.

Your question says "when using a Google browser" - do you see the pop-up even if there is no Avast software installed on the client machine? If so, you need to check the libraries and other sources you're referencing in your web page to make sure there is no malicious content in it.