CVE-2026-55491
BigBlueButton: Stored XSS in Screenshare Recording Playback via Unescaped Meeting Name
CVSS Score
5.4
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-79 |
| Vendor | bigbluebutton |
| Product | bigbluebutton |
| Published | Aug 20, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None
Affected Versions
bigbluebutton / bigbluebutton
< 3.0.29