Stored XSS in Yahoo!

Sharing is Caring :)
When we share, we open doors to a new beginning...../
Well,  now I am going to share how I found Stored Cross-Site Scripting (XSS) in Yahoo.

Steps to Reproduce:
Comment this Payload:
"><img src=x onerror=confirm(1);&gt

Now what? Voila! We get the famous confirm(1) to a popup! :D

I am trying another payload that I can write something in the popup box, and found this payload: 
<img src=x onerror=prompt(1337)>

 That moment I feel like a boss! :P

Here is the video PoC:


31/03/2018 — Initial Report.
01/04/2018 — HackerOne staff asked for Needs more info.
01/04/2018 — More Info Submitted.
04/04/2018 — Triaged and a $300 initial bounty rewarded.
06/04/2018 — Bug Resolved.
11/04/2018 — Another $1700 bounty rewarded. (Total $2000)