CVE-2026-46353: Bigbluebutton

High severity, CVSS 8.1. EPSS: 0.5% chance of exploitation in the next 30 days.

BigBlueButton is an open-source virtual classroom. Prior to 3.0.21, bbb-web checksum validation could be bypassed when a presentationUploadExternalUrl parameter was supplied to API request handling in CreateMeeting.java and ValidationService.java, allowing a user to send valid requests to some endpoints without a checksum. This issue is fixed in version 3.0.21.

Affected products

• Bigbluebutton Bigbluebutton: before 3.0.21 (fixed in 3.0.21)

Published 2026-07-16. Last modified 2026-07-17.