What’s Vulnerable › Vulnerabilities

CVE-2023-43797: BigBlueButton Stored Cross-site Scripting vulnerability at Guest Lobby

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-10-30 · updated 2026-06-17
• Weakness: CWE-79

Description

BigBlueButton is an open-source virtual classroom. Prior to versions 2.6.11 and 2.7.0-beta.3, Guest Lobby was vulnerable to cross-site scripting when users wait to enter the meeting due to inserting unsanitized messages to the element using unsafe innerHTML. Text sanitizing was added for lobby messages starting in versions 2.6.11 and 2.7.0-beta.3. There are no known workarounds.

Affected products

• bigbluebutton: before 2.6.11; 2.7.0-alpha1, 2.7.0-alpha2, 2.7.0-alpha3, 2.7.0-beta1, 2.7.0-beta2 — fixed in 2.6.11

How to fix

Upgrade to a fixed version: bigbluebutton 2.6.11. Check the vendor advisory for mitigations.

References

• https://github.com/bigbluebutton/bigbluebutton/commit/304bc851a00558f99a908880f4ac44234a074c9d
• https://github.com/bigbluebutton/bigbluebutton/pull/18392
• https://github.com/bigbluebutton/bigbluebutton/security/advisories/GHSA-v6wg-q866-h73x
• https://github.com/bigbluebutton/bigbluebutton/commit/304bc851a00558f99a908880f4ac44234a074c9d
• https://github.com/bigbluebutton/bigbluebutton/pull/18392
• https://github.com/bigbluebutton/bigbluebutton/security/advisories/GHSA-v6wg-q866-h73x

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