CVE-2026-41127Network attack vector

Viewer-level caption overwrite via missing submission authorization

Published Apr 21, 2026 · Updated Apr 21, 2026

Authorization bypass in BigBlueButton before 3.0.24 allows remote authenticated users to inject or overwrite meeting captions. The captionSubmitTranscript GraphQL action forwarded submissions without a moderator check, while CaptionApp2x wrote the supplied transcript identifier and text without enforcing the required role. Viewer or non-audio meeting access is sufficient, and the demonstrated consequence is limited to caption integrity.

CVSS severity6.5
Medium
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Authorization bypass in BigBlueButton before 3.0.24 allows remote authenticated users to inject or overwrite meeting captions. The captionSubmitTranscript GraphQL action forwarded submissions without a moderator check, while CaptionApp2x wrote the supplied transcript identifier and text without enforcing the required role. Viewer or non-audio meeting access is sufficient, and the demonstrated consequence is limited to caption integrity.

The record

CVE
CVE-2026-41127
Published
Apr 21, 2026
Updated
Apr 21, 2026
Vendor
BigBlueButton Inc.
Product
BigBlueButton
Classifications
CWE-639, T1565.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 21, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 3.0.24

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

BigBlueButton Inc. · BigBlueButtonversion=< 3.0.24

Published CVSS scores

6.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-639Authorization Bypass Through User-Controlled Key
T1565.001Stored Data Manipulation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo