Medium 5.4Published Aug 20, 2026

CVE-2026-55491BigBlueButton: Stored XSS in Screenshare Recording Playback via Unescaped Meeting Name

Updated under an hour ago (2026-10-19 13:10 UTC)

Does this affect you?

It affects bigbluebutton. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

Do this next

Start free and add your stack

Free account, 1 product

Every CVE for bigbluebutton

Exploited in the last 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.

CVSS: 5.4 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Weakness (CWE): CWE-79
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Aug 21, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

bigbluebutton bigbluebutton bigbluebutton:bigbluebutton (from the name)	before 3.0.29	CNA record

References

https://github.com/bigbluebutton/bigbluebutton/security/advisories/GHSA-57p5-c888-74f9x-refsource-confirm
https://github.com/bigbluebutton/bigbluebutton/commit/a53f2b92022388bfa4109d3136d1f3a932404b1bx-refsource-misc
https://github.com/bigbluebutton/bigbluebutton/releases/tag/v3.0.29x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.