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.

BigBlueButton is an open source web conferencing system. Users in meetings with private chat enabled are vulnerable to a cross site scripting attack in affected versions. The attack occurs when the attacker (with xss in the name) starts a chat. in the victim's client the JavaScript will be executed. This issue has been addressed in version 2.4.8 and 2.5.0. There are no known workarounds for this issue.

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.