CVE-2026-27737

MEDIUM

BigBlueButton has Stored XSS in bbb-playback replay

Title source: cna
STIX 2.1

Description

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.

References (5)

Core 5

Scores

CVSS v3 6.5
EPSS 0.0004
EPSS Percentile 11.0%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-79
Status published
Products (3)
bigbluebutton/bbb-playback < 5.4.3
bigbluebutton/bigbluebutton < 3.0.19
blindsidenetworks/scalite < 1.7.0
Published May 18, 2026
Tracked Since May 19, 2026