---
id: CVE-2026-55491
title: BigBlueButton is an open-source virtual classroom
summary: >-
  BigBlueButton is an open-source virtual classroom. Prior to 3.0.29,
  BigBlueButton failed to escape meetingName in
  record-and-playback/screenshare/playback/index.html.erb when generating the
  screenshare playback format. A low-privileged u…
severity: medium
cvss: 5.4
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N'
cwe:
  - CWE-79
published: '2026-08-20'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T13:42:43.960'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-55491'
references:
  - url: >-
      https://github.com/bigbluebutton/bigbluebutton/commit/a53f2b92022388bfa4109d3136d1f3a932404b1b
    label: security-advisories@github.com
  - url: 'https://github.com/bigbluebutton/bigbluebutton/releases/tag/v3.0.29'
    label: security-advisories@github.com
  - url: >-
      https://github.com/bigbluebutton/bigbluebutton/security/advisories/GHSA-57p5-c888-74f9
    label: security-advisories@github.com
tags:
  - nvd
epss: 0.00289
epssPercentile: 0.19043
ingestedAt: '2026-09-16T13:56:12.596Z'
---

## Overview

BigBlueButton is an open-source virtual classroom. Prior to 3.0.29, BigBlueButton failed to escape meetingName in record-and-playback/screenshare/playback/index.html.erb when generating the screenshare playback format. A low-privileged user could store a crafted meeting name that embedded script content, and the script executed in another user's browser when that user replayed the recording. This issue is fixed in version 3.0.29.

## Remediation

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