CVE-2026-46355 BigBlueButton: Unauthenticated Session Hijack via Exposed /bigbluebutton/api/handleJoinExistingUser
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-46355?
CVE-2026-46355 is a high-severity vulnerability in bigbluebutton, published on 20 Aug 2026.
Official description
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.
Weakness: CWE-287
Which versions are affected by CVE-2026-46355?
How do I fix CVE-2026-46355?
No fix has been published for CVE-2026-46355 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-46355 being exploited?
There is no known exploitation of CVE-2026-46355 in the wild and no public exploit code.
Sources
Also known as GHSA-38fw-2gq7-ccgr.