Take Advantage of Out-of-Scope Domains in Bug Bounty Programs

Cross Site Scripting (XSS)

In brief, you may be able to escalate your attacks by using API’s, javacript workarounds, a misconfiguration on a domain that isn’t under the program scope.

https://ahussam.me/Take-Advantage-of-Out-of-Scope-Domains-in-Bug-Bounty/