Vulnerability · Published Feb 21, 2026 · Assigned by GitHub_M

CVE-2026-27467BigBlueButton: Audio from participants to the server initially unmuted

Low 2.0

In plain English

A low-severity information exposure in bigbluebutton from bigbluebutton. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 11% of all known vulnerabilities).

Severity (CVSS 3.1)2.0Low

Exploit odds (30 days)0.2%top 89.1% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

Vendor	Product	Versions
bigbluebutton	bigbluebutton	< 3.0.20

Weakness: CWE-200 · Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:N/A:N

References

https://github.com/bigbluebutton/bigbluebutton/security/advisories/GHSA-6gj9-5rhm-68j8 x_refsource_CONFIRM
https://github.com/bigbluebutton/bigbluebutton/commit/3aa47832bc2b17178799bd932453c226e8f95703 x_refsource_MISC