Medium severity · published Aug 20, 2026
CVE-2026-55489
BigBlueButton: IDOR on BBB through /api/graphql via POST parameter "presentationId" leads to Authentication Bypass
4.9
CVSS
0.3%
EPSS
No
On KEV
Description
BigBlueButton is an open-source virtual classroom. Prior to 3.0.29, BigBlueButton presenters could submit a presentationId through /api/graphql that identified a presentation belonging to another meeting. akka-bbb-apps/src/main/scala/org/bigbluebutton/core/apps/presentationpod/RemovePresentationPubMsgHdlr.scala did not verify the presentation's meeting identifier before deletion, allowing a presenter who knew the identifier to delete another meeting's presentation and disrupt its availability. This issue is fixed in version 3.0.29.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:L/A:L
Attack vector
Network
Complexity
High
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
Low
Availability
Low
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 24% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
BI
bigbluebutton · bigbluebutton
< 3.0.29 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-55489
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-55489
github.com
https://github.com/bigbluebutton/bigbluebutton/commit/c9e93f9af07b9661e286d101b83cbccb891c551f
github.com
https://github.com/bigbluebutton/bigbluebutton/releases/tag/v3.0.29
github.com
https://github.com/bigbluebutton/bigbluebutton/security/advisories/GHSA-jxpq-r3h3-p75g
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