SB2026022021 - Multiple vulnerabilities in BigBlueButton

Description

This security bulletin contains information about 2 vulnerabilities.

1) Information disclosure (CVE-ID: CVE-2026-27467)

CWE-ID: CWE-200 - Exposure of sensitive information to an unauthorized actor

CVSSv4: CVSS:4.0/AV:N/AC:H/AT:N/PR:H/UI:A/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear

The vulnerability allows a remote user to gain access to potentially sensitive information.

The vulnerability exists due to the client sends audio to the server when first joining a session even with the microphone muted. A remote administrator can gain unauthorized access to sensitive information on the system.

2) Open redirect (CVE-ID: CVE-2026-27736)

CWE-ID: CWE-601 - URL Redirection to Untrusted Site ('Open Redirect')

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear

The vulnerability allows a remote attacker to redirect users to an untrusted site.

The vulnerability exists due to url redirection to an untrusted site in the ApiController respondWithRedirect function when handling the errorRedirectUrl parameter. A remote attacker can supply a crafted redirect URL to redirect users to an untrusted site.

User interaction is required for exploitation.

Remediation

Install update from vendor's website.

References

• https://github.com/bigbluebutton/bigbluebutton/security/advisories/GHSA-6gj9-5rhm-68j8
• https://github.com/bigbluebutton/bigbluebutton/security/advisories/GHSA-65cv-rg9f-qqrx
• https://github.com/advisories/GHSA-65cv-rg9f-qqrx