BigBlueButton is an open-source virtual classroom. In versions 3.0.19 and below, when first joining a session with the microphone muted, the client sends audio to the server regardless of mute state. Media is discarded at the server side, so it isn't audible to any participants, but this may allow for malicious server operators to access audio data. The behavior is only incorrect between joining the meeting and the first time the user unmutes. This issue has been fixed in version 3.0.20.

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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.

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PILOS (Platform for Interactive Live-Online Seminars) is a frontend for BigBlueButton. Prior to 4.10.0, Cross-Site Request Forgery (CSRF) vulnerability exists in an administrative API endpoint responsible for terminating all active video conferences on a single server. The affected endpoint performs a destructive action but is exposed via an HTTP GET request. Although proper authorization checks are enforced and the endpoint cannot be triggered cross-site, the use of GET allows the action to be implicitly invoked through same-site content (e.g. embedded resources rendered within the application). As a result, an authenticated administrator who views crafted content within the application may unknowingly trigger the endpoint, causing all active video conferences on the server to be terminated without explicit intent or confirmation. This vulnerability is fixed in 4.10.0.

thm

PILOS (Platform for Interactive Live-Online Seminars) is a frontend for BigBlueButton. Prior to 4.8.0, users with a local account can change their password while logged in. When doing so, all other active sessions are terminated, except for the currently active one. However, the current session’s token remains valid and is not refreshed. If an attacker has previously obtained this session token through another vulnerability, changing the password will not invalidate their access. As a result, the attacker can continue to act as the user even after the password has been changed. This vulnerability is fixed in 4.8.0.

thm

PILOS (Platform for Interactive Live-Online Seminars) is a frontend for BigBlueButton. PILOS before 4.8.0 exposes the PHP version via the X-Powered-By header, enabling attackers to fingerprint the server and assess potential exploits. This information disclosure vulnerability originates from PHP’s base image. Additionally, the PHP version can also be inferred through the PILOS version displayed in the footer and by examining the source code available on GitHub. This information disclosure vulnerability has been patched in PILOS in v4.8.0.

thm

PILOS (Platform for Interactive Live-Online Seminars) is a frontend for BigBlueButton. PILOS before 4.8.0 includes a Cross-Origin Resource Sharing (CORS) misconfiguration in its middleware: it reflects the Origin request header back in the Access-Control-Allow-Origin response header without proper validation or a whitelist, while Access-Control-Allow-Credentials is set to true. This behavior could allow a malicious website on a different origin to send requests (including credentials) to the PILOS API. This may enable exfiltration or actions using the victim’s credentials if the server accepts those cross-origin requests as authenticated. Laravel’s session handling applies additional origin checks such that cross-origin requests are not authenticated by default. Because of these session-origin protections, and in the absence of any other unknown vulnerabilities that would bypass Laravel’s origin/session checks, this reflected-Origin CORS misconfiguration is not believed to be exploitable in typical PILOS deployments. This vulnerability has been patched in PILOS in v4.8.0

thm

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 crash the chat functionality for all participants in a meeting by sending a malformed `reactionEmojiId` in the GraphQL mutation `chatSendMessageReaction`. Version 3.0.13 contains a patch. No known workarounds are available.

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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.

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BigBlueButton is an open-source virtual classroom. In versions prior to 3.0.13, the "Shared Notes" feature contains a Stored Cross-Site Scripting (XSS) vulnerability with the input location being the "Username" field and the output location on the "Shared Notes" page, when a user with a malicious username is editing content. This vulnerability allows a low-privileged user to execute arbitrary JavaScript in the context of higher-privileged users (e.g., Admins) who open the Shared Notes page. Version 3.0.13 fixes the issue.

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The BigBlueButton plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the the moderator code and viewer code fields in versions up to, and including, 3.0.0-beta.4 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers with author privileges or higher to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link.

BigBlueButton is an open-source virtual classroom designed to help teachers teach and learners learn. An attacker may be able to exploit the overly elevated file permissions in the `/usr/local/bigbluebutton/core/vendor/bundle/ruby/2.7.0/gems/resque-2.6.0` directory with the goal of privilege escalation, potentially exposing sensitive information on the server. This issue has been patched in version(s) 2.6.18, 2.7.8 and 3.0.0-alpha.7.

BigBlueButton is an open-source virtual classroom designed to help teachers teach and learners learn. An attacker with a valid join link to a meeting can trick BigBlueButton into generating a signed join link with additional parameters. One of those parameters may be "role=moderator", allowing an attacker to join a meeting as moderator using a join link that was originally created for viewer access. This vulnerability has been patched in version(s) 2.6.18, 2.7.8 and 3.0.0-alpha.7.

Insufficient capability checks meant it was possible for users to gain access to BigBlueButton join URLs they did not have permission to access.

moodle · fedoraproject

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.

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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.

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When duplicating a BigBlueButton activity, the original meeting ID was also duplicated instead of using a new ID for the new activity. This could provide unintended access to the original meeting.

moodle · fedoraproject

PILOS is an open source front-end for BigBlueButton servers with a built-in load balancer. The password reset component deployed within PILOS uses the hostname supplied within the request host header when building a password reset URL. It may be possible to manipulate the URL sent to PILOS users when so that it points to the attackers server thereby disclosing the password reset token if/when the link is followed. This only affects local user accounts and requires the password reset option to be enabled. This issue has been patched in version 2.3.0.

thm

BigBlueButton is an open-source virtual classroom. BigBlueButton prior to versions 2.6.12 and 2.7.0-rc.1 is vulnerable to Server-Side Request Forgery (SSRF). This issue is a bypass of CVE-2023-33176. A patch in versions 2.6.12 and 2.7.0-rc.1 disabled follow redirect at `httpclient.execute` since the software no longer has to follow it when using `finalUrl`. There are no known workarounds. We recommend upgrading to a patched version of BigBlueButton.

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BigBlueButton is an open-source virtual classroom. Prior to versions 2.6.11 and 2.7.0-beta.3, Guest Lobby was vulnerable to cross-site scripting when users wait to enter the meeting due to inserting unsanitized messages to the element using unsafe innerHTML. Text sanitizing was added for lobby messages starting in versions 2.6.11 and 2.7.0-beta.3. There are no known workarounds.

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BigBlueButton is an open-source virtual classroom. BigBlueButton prior to version 2.6.0-beta.1 has a path traversal vulnerability that allows an attacker with a valid starting folder path, to traverse and read other files without authentication, assuming the files have certain extensions (txt, swf, svg, png). In version 2.6.0-beta.1, input validation was added on the parameters being passed and dangerous characters are stripped. There are no known workarounds.

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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.

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