Vulnerabilities

BigBlueButton is an open-source virtual classroom. In versions on the 3.x branch prior to 3.0.20, the string received with errorRedirectUrl lacks validation, using it directly in the respondWithRedirect function leads to an Open Redirect vulnerability. BigBlueButton 3.0.20 patches the issue. No known workarounds are available.

BigBlueButton is an open-source virtual classroom. In versions 3.0.21 and below, the official documentation for "Server Customization" on Support for ClamAV as presentation file scanner contains instructions that leave a BBB server vulnerable for Denial of Service. The flawed command exposes both ports (3310 and 7357) to the internet. A remote attacker can use this to send complex or large documents to clamd and waste server resources, or shutdown the clamd process. The clamd documentation explicitly warns about exposing this port. Enabling ufw (ubuntu firewall) during install does not help, because Docker routes container traffic through the nat table, which is not managed or restricted by ufw. Rules installed by ufw in the filter table have no effect on docker traffic. In addition, the provided example also mounts /var/bigbluebutton with write permissions into the container, which should not be required. Future vulnerabilities in clamd may allow attackers to manipulate files in that folder. Users are unaffected unless they have opted in to follow the extra instructions from BigBlueButton's documentation. This issue has been fixed in version 3.0.22.

BigBlueButton is an open-source virtual classroom. A Denial of Service (DoS) vulnerability in versions prior to 3.0.13 allows any authenticated user to freeze or crash the entire server by abusing the polling feature's `Choices` response type. By submitting a malicious payload with a massive array in the `answerIds` field, the attacker can cause the current meeting — and potentially all meetings on the server — to become unresponsive. Version 3.0.13 contains a patch. No known workarounds are available.

Greenlight is an end-user interface for BigBlueButton servers. Versions prior to 2.13.0 have an open redirect vulnerability in the Login page due to unchecked the value of the `return_to` cookie. Versions 2.13.0 contains a patch for the issue.

BigBlueButton is an open-source virtual classroom. BigBlueButton prior to version 2.6.0-beta.2 is vulnerable to unrestricted file upload, where the insertDocument API call does not validate the given file extension before saving the file, and does not remove it in case of validation failures. BigBlueButton 2.6.0-beta.2 contains a patch. There are no known workarounds.

BigBlueButton is an open source virtual classroom designed to help teachers teach and learners learn. In affected versions are affected by a Server-Side Request Forgery (SSRF) vulnerability. In an `insertDocument` API request the user is able to supply a URL from which the presentation should be downloaded. This URL was being used without having been successfully validated first. An update to the `followRedirect` method in the `PresentationUrlDownloadService` has been made to validate all URLs to be used for presentation download. Two new properties `presentationDownloadSupportedProtocols` and `presentationDownloadBlockedHosts` have also been added to `bigbluebutton.properties` to allow administrators to define what protocols a URL must use and to explicitly define hosts that a presentation cannot be downloaded from. All URLs passed to `insertDocument` must conform to the requirements of the two previously mentioned properties. Additionally, these URLs must resolve to valid addresses, and these addresses must not be local or loopback addresses. There are no workarounds. Users are advised to upgrade to a patched version of BigBlueButton.

BigBlueButton is an open source web conferencing system. Versions prior to 2.4-rc-6 are vulnerable to Insertion of Sensitive Information Into Sent Data. The moderators-only webcams lock setting is not enforced on the backend, which allows an attacker to subscribe to viewers' webcams, even when the lock setting is applied. (The required streamId was being sent to all users even with lock setting applied). This issue is fixed in version 2.4-rc-6. There are no workarounds.

BigBlueButton is an open source web conferencing system. This vulnerability only affects release candidates of BigBlueButton 2.4. The attacker can start a subscription for poll results before starting an anonymous poll, and use this subscription to see individual responses in the anonymous poll. The attacker had to be a meeting presenter. This issue is patched in version 2.4.0. There are no workarounds.

BigBlueButton before 2.2.7 does not have a protection mechanism for separator injection in meetingId, userId, and authToken.

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.

Greenlight is a simple front-end interface for your BigBlueButton server. In affected versions an attacker can view any room's settings even though they are not authorized to do so. Only the room owner and administrator should be able to view a room's settings. This issue has been patched in release version 2.12.6.

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.

BigBlueButton Greenlight 2.11.1 allows XSS. A threat actor could have a username containing a JavaScript payload. The payload gets executed in the browser of the victim in the "Share room access" dialog if the victim has shared access to the particular room with the attacker previously.

BigBlueButton is an open source web conferencing system. Starting in version 2.2 and prior to versions 2.3.18 and 2.4-rc-6, an attacker who is able to obtain the meeting identifier for a meeting on a server can find information related to an external video being shared, like the current timestamp and play/pause. The problem has been patched in versions 2.3.18 and 2.4-rc-6 by modifying the stream to send the data only for users in the meeting. There are currently no known workarounds.

BigBlueButton is an open source web conferencing system. Versions starting with 2.2 and prior to 2.3.19, 2.4.7, and 2.5.0-beta.2 are vulnerable to regular expression denial of service (ReDoS) attacks. By using specific a RegularExpression, an attacker can cause denial of service for the bbb-html5 service. The useragent library performs checking of device by parsing the input of User-Agent header and lets it go through lookupUserAgent() (alias of useragent.lookup() ). This function handles input by regexing and attackers can abuse that by providing some ReDos payload using `SmartWatch`. The maintainers removed `htmlclient/useragent` from versions 2.3.19, 2.4.7, and 2.5.0-beta.2. As a workaround, disable NginX forwarding the requests to the handler according to the directions in the GitHub Security Advisory.

Cross-site Scripting (XSS) - Generic in GitHub repository bigbluebutton/bigbluebutton prior to 2.4.0.

An issue was discovered in BigBlueButton through 2.2.29. When at attacker is able to view an account_activations/edit?token= URI, the attacker can create an approved user account associated with an email address that has an arbitrary domain name.

web/controllers/ApiController.groovy in BigBlueButton before 2.2.29 lacks certain parameter sanitization, as demonstrated by accepting control characters in a user name.

A cross-site scripting (XSS) vulnerability exists in the 'merge account' functionality in admins.js in BigBlueButton Greenlight 2.7.6.

BigBlueButton through 2.2.28 uses Ghostscript for processing of uploaded EPS documents, and consequently may be subject to attacks related to a "schwache Sandbox."