CVE-2026-55491: Bigbluebutton

Medium severity, CVSS 5.4. EPSS: 0.3% chance of exploitation in the next 30 days.

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.

Affected products

• Bigbluebutton Bigbluebutton: before 3.0.29 (fixed in 3.0.29)

Published 2026-08-20. Last modified 2026-09-16.