CVE-2026-46353 BigBlueButton API checksum bypass via presentationUploadExternalUrl
Attackers can bypass API checksum validation in BigBlueButton to send valid requests to certain endpoints without proper authentication signatures.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-46353?
CVE-2026-46353 is a high-severity vulnerability in bigbluebutton, published on 16 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
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.
Weakness: CWE-284
Which versions are affected by CVE-2026-46353?
How do I fix CVE-2026-46353?
No fix has been published for CVE-2026-46353 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-46353 being exploited?
There is no known exploitation of CVE-2026-46353 in the wild and no public exploit code.
Sources
Also known as GHSA-43hc-5g2m-cqff.