CVE-2026-55491

EUVD-2026-63682

20.08.2026, 22:17

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.

Cross-site Scripting

Provider	Type	Base Score	Atk. Vector	Atk. Complexity	Priv. Required	Vector
GitHub_M	CNA	5.4 MEDIUM	NETWORK	LOW	LOW	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Base Score

CVSS 3.x

EPSS Score

Percentile: Unknown

Early Detection

Affected products identified ahead of NVD analysis through intelligence sources.

Vendor	Product	Version	Source
bigbluebutton	bigbluebutton	𝑥 < 3.0.29	CNA

Common Weakness Enumeration

CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
The software does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

References

https://github.com/bigbluebutton/bigbluebutton/commit/a53f2b92022388bfa4109d3136d1f3a932404b1b

https://github.com/bigbluebutton/bigbluebutton/releases/tag/v3.0.29

https://github.com/bigbluebutton/bigbluebutton/security/advisories/GHSA-57p5-c888-74f9