Versions of next prior to 5.1.0 are vulnerable to Remote Code Execution. The /path: route fails to properly sanitize input and passes it to a require() call. This allows attackers to execute JavaScript code on the server. Note that prior version 0.9.9 package next npm package hosted a different utility (0.4.1 being the latest version of that codebase), and this advisory does not apply to those versions.
Recommendation
Upgrade to version 5.1.0.