Medium severity · published Feb 25, 2026
CVE-2026-27736
BigBlueButton has Open Redirect vulnerability in ApiController
6.1
CVSS
0.2%
EPSS
No
On KEV
Description
BigBlueButton is an open-source virtual classroom. In versions on the 3.x branch prior to 3.0.20, the string received with errorRedirectUrl lacks validation, using it directly in the respondWithRedirect function leads to an Open Redirect vulnerability. BigBlueButton 3.0.20 patches the issue. No known workarounds are available.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 7% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
BI
bigbluebutton · bigbluebutton
>= 3.0.0, < 3.0.20 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-27736
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-27736
Patch
https://github.com/bigbluebutton/bigbluebutton/commit/691f92f3af0d6b796b91cb968977068663119812
Patch
https://github.com/bigbluebutton/bigbluebutton/security/advisories/GHSA-65cv-rg9f-qqrx
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