Read the docs
TI-2026-21874 Aliases CVE-2026-27467

BigBlueButton: Audio from participants to the server initially unmuted

Priority LOW 12CWE-200Published · Updated

Key facts

Attack vector
Network
Privileges required
High
User interaction
Required
Attack complexity
Low
Impact type
Information disclosure
Confidentiality · integrity · availability
Low · None · None
Fix status
Fixed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-200.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00207 10th percentileScored 2026-11-07
Fix Fixed bigbluebutton (bigbluebutton): 3.0.20

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
bigbluebuttonbigbluebuttonbefore 3.0.203.0.20Patch availableCNA
  • bigbluebutton Vendorbigbluebutton Affected before 3.0.20 Fixed in 3.0.20 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:bigbluebutton:bigbluebutton:*:*:*:*:*:*:*:*before 3.0.20Vulnerablebigbluebutton
  • cpe:2.3:a:bigbluebutton:bigbluebutton:*:*:*:*:*:*:*:* Versions before 3.0.20 Vulnerable ·bigbluebutton

Remediation

  • Fix · CNA bigbluebutton (bigbluebutton) Fixed in 3.0.20

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-27467

References

Patch 2

  • TI-2026-21873 BigBlueButton: Exposed ClamAV port enables Denial of Service CVSS 3.1HIGH 8.2
  • TI-2025-38047 BigBlueButton vulnerable to Chat DoS via invalid reactionEmojiId CVSS 3.1HIGH 7.5
  • TI-2025-38046 BigBlueButton vulnerable to DoS via PollSubmitVote GraphQL mutation CVSS 3.1HIGH 7.5
  • TI-2022-13109 Cross site scripting in username that will trigger by sending chat CVSS 3.1MEDIUM 6.5
  • TI-2020-09954 BigBlueButton before 2.2.6 allows remote attackers to read arbitrary files because the… CVSS 3.1CRITICAL 9.8
  • TI-2020-16722 BigBlueButton through 2.2.28 uses Ghostscript for processing of uploaded EPS documents… CVSS 3.1CRITICAL 9.8
See all 48 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences