Bigbluebutton
CVE-2026-27467
LOW
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A01:2021 - Broken Access Control
ASVS 5.0
V4 - Access Control Authorization enforcement, RBAC validation
MITRE ATT&CK
2 techniques across 2 tactics: Collection, Discovery The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS 2.0 (LOW). Attack vector: Network. Complexity: High. Privileges required: High. User interaction: Required. |
| Exploit ScenarioDerived | An attacker could exploit this vulnerability to for malicious server operators to access audio data. |
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Alert meAnalysisAIv1 – Mar 12, 2026
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. [CVSS 2.0 LOW]
RemediationAI
A vendor patch is available — apply it immediately. Fixed in version 3.0.20.. Restrict network access to the affected service where possible.
Affects your stack
Find out whether the stacks and servers you run are on an affected version.
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
Classified as CWE-200 (Information Exposure). Affects Bigbluebutton. 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.
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Severity by source
AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:N/A:N
Primary rating from GitHub Advisory · only source for this CVE.
CVSS VectorGitHub Advisory
Lifecycle Timeline
2DescriptionGitHub Advisory
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.
Executive ViewAI
CVE-2026-27467 is a low-severity vulnerability in BigBlueButton involving information exposure (CVSS 2.0). The limited severity suggests constrained impact, typically requiring specific conditions or local access for exploitation. A patch is available and can be applied during standard maintenance windows.
Apply vendor patch during routine maintenance. Standard information disclosure mitigations apply if patching is delayed.
Threat Intelligence Overview
NVD
CVE.org
EPSS
GitHub
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.
Affected Products (CPE)GitHub Advisory
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