How it was found

There's a stored xss vulnerability ....

Proof Of Concept :

1. Set name as an xss payload like "x><img src=a onerror=alert(1)>. {F143238}
2. Invite people to single call room.
3. Xss will execute in IE. (It doesn't support CSP) {F143237}

Impact :

Admin user can be xssed via this method if admin uses browsers like IE.

Let me know if you need help in reproducing