Information disclosure in Bigbluebutton
CVE-2026-27467
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.
Vulnerability class: Information Disclosure
EPSS: 0.002 (7.1th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 2.0 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:N/A:N.
Affected products
- Bigbluebutton — versions < 3.0.20
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Patch, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-27467?
- CVE-2026-27467 is a low-severity vulnerability in Bigbluebutton, classified under Information Disclosure. CVSS score: 2.0/10. Published 2026-02-21.
- How severe is CVE-2026-27467?
- Low severity. CVSS v3 base score is 2.0 out of 10.