Stored XSS in Yahoo!

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Well, This is Shahzada Al Shahriar Khan. And I am from Bangladesh.
Now I am going to share how I found Stored Cross-Site Scripting (XSS) in Yahoo.

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

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

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

 That moment I feel like a boss!

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 — $1700 bounty rewarded. ( Total $2000 )

My previous write-up: