The installation procedure in BigBlueButton before 2.2.28 (or earlier) exposes certain network services to external interfaces, and does not automatically set up a firewall configuration to block external access.
Greenlight in BigBlueButton through 2.2.28 places usernames in room URLs, which may represent an unintended information leak to users in a room, or an information leak to outsiders if any user publishes a screenshot of a browser window.
The installation procedure in BigBlueButton before 2.2.28 (or earlier) uses ClueCon as the FreeSWITCH password, which allows local users to achieve unintended FreeSWITCH access.
BigBlueButton before 2.3 does not implement LibreOffice sandboxing. This might make it easier for remote authenticated users to read the API shared secret in the bigbluebutton.properties file. With the API shared secret, an attacker can (for example) use api/join to join an arbitrary meeting regardless of its guestPolicy setting.
BigBlueButton before 2.2.7 allows remote authenticated users to read local files and conduct SSRF attacks via an uploaded Office document that has a crafted URL in an ODF xlink field.
BigBlueButton before 2.2.6 allows remote attackers to read arbitrary files because the presfilename (lowercase) value can be a .pdf filename while the presFilename (mixed case) value has a ../ sequence. This can be leveraged for privilege escalation via a directory traversal to bigbluebutton.properties. NOTE: this issue exists because of an ineffective mitigation to CVE-2020-12112 in which there was an attempted fix within an NGINX configuration file, without considering that the relevant part of NGINX is case-insensitive.