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


Reported on

Dec 29th 2021


The Convos is an open source multi-user chat that runs in a web browser. Characters starting with "https://" in the chat window create <a> tag. Stored XSS vulnerability using onfocus and autofocus occurs because escaping exists for "<" or ">" but escaping for double quarter does not exist.

Proof of Concept

Username :
Password : qwer12211@

1. Open the and Login as to above account
2. Go to<chat room name>
3. In chat room. Enter the https://x."//onfocus="alert(document.domain)"//autofocus="" b="

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
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
Pocas has been awarded the disclosure bounty
The fix bounty is now up for grabs
convos-chat/convos maintainer marked this as fixed in v6.49 with commit 86b219 2 years ago
The fix bounty has been dropped
This vulnerability will not receive a CVE
I18N.js#L158L168 has been validated
convos-chat/convos maintainer
2 years ago


Thank you - I screwed up pretty badly in v6.43 :(

Happy new year!

2 years ago


No :) Thanks for the patch.

Happy New Year. You did a great job this year too :)

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