What is CVE-2026-46355?

CVE-2026-46355 is a high-severity vulnerability in Bigbluebutton, classified under Improper Authentication. CVSS score: 7.1/10. Published 2026-08-20.

How severe is CVE-2026-46355?

High severity. CVSS v3 base score is 7.1 out of 10.

Auth bypass in Bigbluebutton

CVE-2026-46355

BigBlueButton is an open-source virtual classroom. Prior to 3.0.23, BigBlueButton exposed /bigbluebutton/api/handleJoinExistingUser through bigbluebutton-web/grails-app/controllers/org/bigbluebutton/web/controllers/ApiController.groovy. A requester able to supply an existingUserID for an active participant could reuse that participant's session and impersonate the participant in the same meeting because handleJoinExistingUser was a routable controller action rather than a private helper. This issue is fixed in version 3.0.23.

Vulnerability class: Broken Authentication

CVSS v3 metric

CVSS v3 base score 7.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N.

Affected products

Bigbluebutton — versions < 3.0.23

Weakness classification (CWE)

CWE-287 — Improper Authentication

References

security-advisories@github.com (x_refsource_CONFIRM)
security-advisories@github.com (x_refsource_MISC)
security-advisories@github.com (x_refsource_MISC)

Frequently asked questions

What is CVE-2026-46355?: CVE-2026-46355 is a high-severity vulnerability in Bigbluebutton, classified under Improper Authentication. CVSS score: 7.1/10. Published 2026-08-20.
How severe is CVE-2026-46355?: High severity. CVSS v3 base score is 7.1 out of 10.