CVE-2026-27737
CWE-79Published: May 18, 2026· Updated: May 19, 2026
Official 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.
Technical Analysis
CVE-2026-27737 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
A successful exploit results in full integrity compromise (data manipulation), with a CVSS base score of 6.5.
From a weakness classification perspective (CWE-79): Cross-site scripting (XSS) vulnerabilities allow attackers to inject malicious scripts into web pages viewed by other users.
CVSS v3.1 Vector Breakdown
Exploit & PoC Resources
All References (5)
Quick Facts
Related CVEs (CWE-79)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-27737 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts