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

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.

Published: 2026-02-21 Last update: 2026-02-26 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-27467 is rated Low Risk (10.4/100): CVSS Low severity, with low exploitation likelihood (EPSS 0.03%). Low composite risk—no urgent action required; patch on your normal maintenance cycle and revisit priority if CVSS or EPSS increases.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-27467

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-02-21 — 0.03% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-27467

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
2.0 3.1 LOW
CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 0.5 1.4 [email protected]
2.4 3.1 LOW
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 0.9 1.4 [email protected]

Weakness enumeration for CVE-2026-27467

Affected software / configurations for CVE-2026-27467

Vendor Product Version Raw CPE
bigbluebutton bigbluebutton < 3.0.20 cpe:2.3:a:bigbluebutton:bigbluebutton:*:*:*:*:*:*:*:*

References for CVE-2026-27467

cvelogic Threat Intelligence