CVE-2026-27737

BigBlueButton has Stored XSS in bbb-playback replay

MEDIUM
6.5
CVSS Score
Published: May 18, 2026 at 09:11 PM UTC
Updated: July 24, 2026 at 01:23 PM UTC
3 products affected across 2 vendorsBigbluebuttonBbb PlaybackScalelite

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.3%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 5.4.3
Affected range stops below 5.4.3, so it looks safe — our inference, not a vendor statement
v < 3.0.19
Affected range stops below 3.0.19, so it looks safe — our inference, not a vendor statement
v < 1.7.0
Affected range stops below 1.7.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.5MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-79

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