Description

Stored XSS via uploading file in .m3u8a format.

Proof of Concept

filename="poc.m3u8a"

<script>alert(1)</script>

Steps to Reproduce

1.Login into showdoc.com.cn.
2.Navigate to file library (https://www.showdoc.com.cn/attachment/index)
3.In the File Library page, click the Upload button and choose the poc.m3u8a file.
4.After uploading the file, click on the check button to open that file in a new tab.

XSS will trigger when the attachment is opened in a new tab.

POC URLs:https://www.showdoc.com.cn/server/api/attachment/visitFile?sign=b9afd9c1b547da6ca613714c88f239e7

Impact

An attacker can perform social engineering on users by redirecting them from a real website to a fake one. a hacker can steal their cookies etc.