Next.js versions before 9.3.2 are vulnerable to local file inclusion. An attacker can craft special requests to access files in the dist directory (.next). This does not affect files outside of the dist directory (.next). In general, the dist directory only holds build assets unless your application intentionally stores other assets under this directory.
View the template here CVE-2020-5284.yaml
References:
https://github.com/zeit/next.js/releases/tag/v9.3.2