CVE-2026-27737

BigBlueButton has Stored XSS in bbb-playback replay

CVSS 6.5 MEDIUMEPSS 0.3%CWE-79

Vexday Risk Score

13Low

SSVC decision (CISA)

Track

No exploitation signal → monitor

CVSS 6.5EPSS 0.3%KEV nãoPoC —Nuclei —Metasploit —Patch —

Lifecycle

18 May 2026Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

BigBlueButton is an open-source virtual classroom. In versions prior to 3.0.19, the recording playback (presentation format) was not sanitizing user's input in public chat. This allowed for a malicious actor to craft and carry out a targeted XSS attack, activated on anyone replaying the recording. This issue has been fixed 3.0.19.

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

Affected products

bigbluebutton · bbb-playback bigbluebutton · bigbluebutton blindsidenetworks · scalite

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References

https://github.com/bigbluebutton/bbb-playback/commit/09e89bfe4ff8488b68c3ff040d3081e419dc89b1 https://github.com/bigbluebutton/bigbluebutton/commit/69f45aa1b963dc7d80179d0155acc670aec5c4fc https://github.com/bigbluebutton/bigbluebutton/releases/tag/v3.0.19 https://github.com/bigbluebutton/bigbluebutton/security/advisories/GHSA-8vv7-vj94-q2pv https://github.com/blindsidenetworks/scalelite/releases/tag/v1.7.0