CVE-2026-46353 [HIGH] – BigBlueButton is an open-source virtual classroom. Prior to 3.0.21, bbb-web checksum valid

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.