BigBlueButton 2.3 / 2.4.7 Cross Site Scripting

`CVE-2022-31064 - Stored Cross-Site Scripting in BigBlueButton.  
  
=========================  
  
Exploit Title: Stored Cross-Site Scripting (XSS) in BigBlueButton  
  
Product: BigBlueButton  
  
Vendor: BigBlueButton  
  
Vulnerable Versions: 2.3, <2.4.8, <2.5.0  
  
Tested Version: 2.4.7  
  
Advisory Publication: Jun 22, 2022  
  
Latest Update: Jun 22, 2022  
  
Vulnerability Type: Cross-Site Scripting [CWE-79]  
  
CVE Reference: CVE-2022-31064  
  
CVSS Severity: High  
  
CVSS Score: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N  
Impact score: 7.2  
  
Credit: Rick Verdoes & Danny de Weille (Hackify | pentests.nl)  
=========================  
  
  
I. BACKGROUND  
  
-------------------------  
BigBlueButton is an open source web conferencing system designed for online meetings and online learning. BigBlueButton is a tool used by instructors and teachers, which helps them access to Learning Management Systems, engagement tools and analytics.  
  
II. VULNERABILITY  
-------------------------  
Users in meetings with private chat enabled are vulnerable to a cross site scripting attack in affected versions. The attack occurs when the attacker (with a XSS payload in the name) starts a chat. in the victim's client the JavaScript will be executed. This issue has been addressed in version 2.4.8 and 2.5.0. There are no known workarounds for this issue.  
  
III. Proof of Concept  
-------------------------  
<img x onerror=alert()>  
  
IV. References  
-------------------------  
Security advisory https://pentests.nl/pentest-blog/stored-xss-in-bigbluebutton/  
Patched on BigBlueButton 2.5 (https://github.com/bigbluebutton/bigbluebutton/pull/15067)  
Patched on BigBlueButton 2.4 (https://github.com/bigbluebutton/bigbluebutton/pull/15090)  
  
  
  
`