CVE-2026-27736: BigBlueButton is an open-source virtual classroom

Q: How do I fix CVE-2026-27736?

bigbluebutton: upgrade to 3.0.20. Exact commands for each OS are on this page.

Q: Is CVE-2026-27736 being exploited?

CVE-2026-27736 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-2026-27736 affect?

CVE-2026-27736 affects bigbluebutton. Severity is medium (CVSS 6.1). BigBlueButton is an open-source virtual classroom. In versions on the 3.x branch prior to 3.0.20, the string received with errorRedirectUrl lacks validation, using it directly in the respondWithRedirect function leads to an Open Redirect vu

Q: How urgent is CVE-2026-27736?

Priority 23/100. No elevated risk signals yet.

Routine

MEDIUM 6.1UPGRADE

CVE-2026-27736 is a medium-severity flaw (CVSS 6.1) 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 on the 3.x branch prior to 3.0.20, the string received with errorRedirectUrl lacks validation, using it directly in the respondWithRedirect function leads to an Open Redirect vulnerability. BigBlueButton 3.0.20 patches the issue. No known workarounds are available.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	6.1 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.2% (top 93%)
CISA exploited list	No
Weakness	CWE-601
Published	2026-02-25
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

2026-02-25 17:25 UTCPublished CVE record published
2026-06-17 10:27 UTCUpdated Record last modified

bigbluebutton bigbluebutton UPGRADE

Affected: < 3.0.20

Fixed in: 3.0.20

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 3.0.20 (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-2026-27736?

bigbluebutton: upgrade to 3.0.20. Exact commands for each OS are on this page.

Is CVE-2026-27736 being exploited?

CVE-2026-27736 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-2026-27736 affect?

CVE-2026-27736 affects bigbluebutton. Severity is medium (CVSS 6.1). BigBlueButton is an open-source virtual classroom. In versions on the 3.x branch prior to 3.0.20, the string received with errorRedirectUrl lacks validation, using it directly in the respondWithRedirect function leads to an Open Redirect vu

How urgent is CVE-2026-27736?

Priority 23/100. No elevated risk signals yet.

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-2026-27467 LOW 2.0 UPGRADE BigBlueButton is an open-source virtual classroom
CVE-2026-27466 HIGH 7.2 UPGRADE BigBlueButton is an open-source virtual classroom

References

← Back to latest CVEs