Bigbluebutton: >> Bigbluebutton Security 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.
CVSS Score
6.1
EPSS Score
0.0
Published
2026-02-25
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.
CVSS Score
7.2
EPSS Score
0.001
Published
2026-02-21
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.
CVSS Score
2.0
EPSS Score
0.0
Published
2026-02-21
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.
CVSS Score
7.5
EPSS Score
0.001
Published
2025-10-09
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.
CVSS Score
7.5
EPSS Score
0.001
Published
2025-10-09
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.
CVSS Score
7.1
EPSS Score
0.0
Published
2025-10-09
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.
CVSS Score
6.3
EPSS Score
0.001
Published
2023-10-30
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.
CVSS Score
5.6
EPSS Score
0.0
Published
2023-10-30
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.
CVSS Score
3.1
EPSS Score
0.002
Published
2023-10-30
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.
CVSS Score
5.3
EPSS Score
0.001
Published
2023-10-30
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