Bigbluebutton Cross-site Scripting

BigBlueButton is an open source web conferencing system. In affected versions an attacker can embed malicious JS in their username and have it executed on the victim's client. When a user receives a private chat from the attacker (whose username contains malicious JavaScript), the script gets executed. Additionally when the victim receives a notification that the attacker has left the session. This issue has been patched in version 2.4.8 and 2.5.0. There are no known workarounds for this issue. (2022-06-27, CVE-2022-31065)

BigBlueButton is an open source web conferencing system. 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 xss 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. (2022-06-27, CVE-2022-31064)

BigBlueButton version 2.4.7 (or earlier) is vulnerable to stored Cross-Site Scripting (XSS) in the private chat functionality. A threat actor could inject JavaScript payload in his/her username. The payload gets executed in the browser of the victim each time the attacker sends a private message to the victim or when notification about the attacker leaving room is displayed. (2022-06-24, CVE-2022-27238)

Cross-site Scripting (XSS) - Generic in GitHub repository bigbluebutton/bigbluebutton prior to 2.4.0. (2022-01-19, CVE-2021-4143)

In BigBlueButton before 2.2.28 (or earlier), uploaded presentations are sent to clients without a Content-Type header, which allows XSS, as demonstrated by a .png file extension for an HTML document. (2020-10-21, CVE-2020-27608)

BigBlueButton before 2.2.4 allows XSS via closed captions because dangerouslySetInnerHTML in React is used. (2020-04-23, CVE-2020-12113)

Cross site scripting is an attack where a web page executes code that is injected by an adversary. It usually appears, when users input is presented. This attack can be used to impersonate a user, take over control of the session, or even steal API keys.

The attack can be executed e.g. when you application injects the request parameter directly into the HTML code of the page returned to the user:

https://server.com/confirmation?message=Transaction+Complete

what results in:

<span>Confirmation: Transaction Complete</span>

In that case the message can be modified to become a valid Javascript code, e.g.:

https://server.com/confirmation?message=<script>dangerous javascript code here</script>

and it will be executed locally by the user's browser with full access to the user's personal application/browser data:

<span>Confirmation: <script>dangerous javascript code here</script></span>