---
id: CVE-2026-46355
title: BigBlueButton is an open-source virtual classroom
summary: >-
  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.
  …
severity: high
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N'
cwe:
  - CWE-287
published: '2026-08-20'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T13:42:43.933'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-46355'
references:
  - url: >-
      https://github.com/bigbluebutton/bigbluebutton/commit/972b04e474e195cbd708b5b3f0485fe528a1a85b
    label: security-advisories@github.com
  - url: 'https://github.com/bigbluebutton/bigbluebutton/releases/tag/v3.0.23'
    label: security-advisories@github.com
  - url: >-
      https://github.com/bigbluebutton/bigbluebutton/security/advisories/GHSA-38fw-2gq7-ccgr
    label: security-advisories@github.com
tags:
  - nvd
epss: 0.0021
epssPercentile: 0.11479
ingestedAt: '2026-09-16T13:56:12.595Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.