XSS Payload : <img src=x onerror=alert('xss') >

Steps to reproduce:
1. Install subscribe2 plugin (
2. Install FluentSMTP
3. Configure FluentSMTP to use custom SMTP (for testing use mailtrap).
4. As another user (needs Author+ role), send an email using subscribe2 plugin with email content as xss payload.
5. View logs and click on preview icon to trigger XSS.