android Cross-app scripting .... I'm still struggling with this problem

Question

I registered the app.

After registering,

Cross-app scripting. The app includes WebView, which is vulnerable to cross-app scripting. For more information, check out Google Customer Center Help.

com.xxxxxx.xxxxxx.ui.main.MainActivity->onNewIntent sv:deadline:05/23/2022

I received the above information.

Since then, I have blocked ways to attack from the outside.

if(url.startsWith(BuildConfig.BASE_URL)){
//Use an internal site.
}else{ 
// Blocking external sites
}

I don't know exactly what the problem is.

I need help.