High · published October 10, 2025
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.
| Product | Versions | Fixed in |
|---|---|---|
| bigbluebutton/bigbluebutton | < 3.0.13 | 3.0.13 |