CVE-2026-27466: BigBlueButton is an open-source virtual classroom

Q: How do I fix CVE-2026-27466?

bigbluebutton: upgrade to 3.0.22. Exact commands for each OS are on this page.

Q: Is CVE-2026-27466 being exploited?

CVE-2026-27466 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-27466 affect?

CVE-2026-27466 affects bigbluebutton. Severity is high (CVSS 7.2). BigBlueButton is an open-source virtual classroom. In versions 3.0.21 and below, the official documentation for "Server Customization" on Support for ClamAV as presentation file scanner contains instructions that leave a BBB server vulnerab

Q: How urgent is CVE-2026-27466?

Priority 45/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

HIGH 7.2REMOTEUPGRADE

CVE-2026-27466 is a high-severity flaw (CVSS 7.2) affecting bigbluebutton. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

BigBlueButton is an open-source virtual classroom. In versions 3.0.21 and below, the official documentation for "Server Customization" on Support for ClamAV as presentation file scanner contains instructions that leave a BBB server vulnerable for Denial of Service. The flawed command exposes both ports (3310 and 7357) to the internet. A remote attacker can use this to send complex or large documents to clamd and waste server resources, or shutdow

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.2 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 61%)
CISA exploited list	No
Weakness	CWE-668
Published	2026-02-21
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: bigbluebutton

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-02-21 08:16 UTCPublished CVE record published
2026-06-17 10:27 UTCUpdated Record last modified

bigbluebutton bigbluebutton UPGRADE

Affected: < 3.0.22

Fixed in: 3.0.22

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy bigbluebutton || rpm -q bigbluebutton || bigbluebutton --version

2. UPGRADE to 3.0.22 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade bigbluebutton

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade bigbluebutton

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-27466?

bigbluebutton: upgrade to 3.0.22. Exact commands for each OS are on this page.

Is CVE-2026-27466 being exploited?

CVE-2026-27466 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-27466 affect?

CVE-2026-27466 affects bigbluebutton. Severity is high (CVSS 7.2). BigBlueButton is an open-source virtual classroom. In versions 3.0.21 and below, the official documentation for "Server Customization" on Support for ClamAV as presentation file scanner contains instructions that leave a BBB server vulnerab

How urgent is CVE-2026-27466?

Priority 45/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2025-61601 HIGH 7.5 UPGRADE BigBlueButton is an open-source virtual classroom
CVE-2025-61602 HIGH 7.5 UPGRADE BigBlueButton is an open-source virtual classroom
CVE-2025-55200 HIGH 7.1 UPGRADE BigBlueButton is an open-source virtual classroom
CVE-2026-27736 MEDIUM 6.1 UPGRADE BigBlueButton is an open-source virtual classroom
CVE-2026-27467 LOW 2.0 UPGRADE BigBlueButton is an open-source virtual classroom

References

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