CVE-2026-27737CWE-79

BigBlueButton has Stored XSS in bbb-playback replay

Medium · published May 18, 2026

CVSS v3.1
6.5
EPSS
0%
Percentile
36.0
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
6.5 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
CVSS v4.0
Not supplied
EPSS
0.00428 · 36.0th percentile
Weakness
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published
2026-05-18T21:11Z
EPSS history
Timeline
  • 18 MAY 21:11Z
    BigBlueButton has Stored XSS in bbb-playback replay
    cvelistv5