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)