Cross-site Scripting (XSS) - Stored in convos-chat/convos


Reported on

Dec 28th 2021


The Convos is an open source multi-user chat that runs in a web browser. You can't use SVG extension in Convos' chat window, but you can upload .html extension. This causes Stored XSS. Also, after uploading a file, it does not log in, and XSS occurs even if you connect.

Proof of Concept

Username :
Password : qwer12211@

1. Open the and Login as to above account
2. Go to<chat room name>
3. File Upload a html file 
4. When you upload a file, an upload link is created in the comment form.
5. Please connect after attaching ".html" after the link

Video :


Through this vulnerability, an attacker is capable to execute malicious scripts.

We are processing your report and will contact the convos-chat/convos team within 24 hours. 2 years ago
A GitHub Issue asking the maintainers to create a exists 2 years ago
Pocas modified the report
2 years ago
We have contacted a member of the convos-chat/convos team and are waiting to hear back 2 years ago
convos-chat/convos maintainer validated this vulnerability 2 years ago
p0cas has been awarded the disclosure bounty
The fix bounty is now up for grabs
convos-chat/convos maintainer marked this as fixed in 6.48 with commit 5c0a1e 2 years ago
The fix bounty has been dropped
convos-chat/convos maintainer
2 years ago


Thank you! Appreciate it :)

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