CVE-2026-46353

BigBlueButton API checksum bypass via presentationUploadExternalUrl

8.1 High

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.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: Low
User interaction: None

What an attacker can affect

Confidentiality: High
Integrity: High
Availability: None

Exploit likelihood

0.48%Up 0.4 points since Jun 12, 2026

What each source reports

CVE List Score used 8.1

BigBlueButton API checksum bypass via presentationUploadExternalUrl

Record: CVE-2026-46353
CVSS 3.1: 8.1 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Weakness: CWE-284
Updated: 2026-11-02

EUVDEUVD-2026-44998 8.1

Record: EUVD-2026-44998
CVSS 3.1: 8.1 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Updated: 2026-11-02

NVD 8.1

Record: CVE-2026-46353
CVSS 3.1: 8.1 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Weakness: CWE-284
Updated: 2026-11-02

OSV 8.1

BigBlueButton API checksum bypass via presentationUploadExternalUrl

Record: CVE-2026-46353
CVSS 3.1: 8.1 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Weakness: CWE-284
Updated: 2026-11-02

Affected products

bigbluebutton

History

History
Recorded	Changed	Sources
Nov 2, 2026	first indexed	CVE List, EUVD, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-46353 is a high vulnerability (CVSS 8.1) in Bigbluebutton, published July 16, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.48%, the 41st percentile. No source names a fixed version.