EUVD-2026-44998Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Access control enforcement
MITRE ATT&CK
1 technique across 1 tactic: Defense Evasion The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
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Alert meAnalysisAIv1 – Jul 16, 2026
Authentication/access-control bypass in BigBlueButton's bbb-web component (versions prior to 3.0.21) lets remote attackers reach protected API endpoints without a valid checksum by supplying the presentationUploadExternalUrl parameter. BigBlueButton's API is normally guarded by a shared-secret checksum, so bypassing it undermines the core authorization mechanism for calls such as CreateMeeting. No public exploit identified at time of analysis, though the fixing commit is public; CVSS is 8.1 and there is no CISA KEV listing or EPSS signal in the provided data.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in euvd
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Severity by source
AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Primary rating from Vendor (GitHub_M) · only source for this CVE.
CVSS VectorVendor: GitHub_M
Lifecycle Timeline
2DescriptionCVE.org
BigBlueButton is an open-source virtual classroom. Prior to 3.0.21, bbb-web checksum validation could be bypassed when a presentationUploadExternalUrl parameter was supplied to API request handling in CreateMeeting.java and ValidationService.java, allowing a user to send valid requests to some endpoints without a checksum. This issue is fixed in version 3.0.21.
Articles & Coverage 1
Executive ViewAI
BigBlueButton bbb-web component versions prior to 3.0.21 contain an authentication bypass vulnerability (CVE-2026-46353, CVSS 8.1) allowing remote attackers to circumvent the shared-secret checksum and invoke protected API endpoints such as CreateMeeting without proper authorization. This undermines the primary authorization mechanism protecting all 2.x deployments, enabling unauthorized meeting creation, configuration, and data access. Organizations running unpatched BigBlueButton infrastructure face immediate risk of unauthorized use.
Within 24 hours, identify and document all BigBlueButton deployments and their current versions to determine exposure scope. Within 7 days, for any instances running versions prior to 3.0.21, implement network-level access controls restricting bbb-web API endpoints to authorized callers only, enable detailed audit logging on CreateMeeting and administrative API calls, and establish monitoring for requests attempting to bypass checksum validation. Within 30 days, upgrade all affected BigBlueButton instances to version 3.0.21 or later.
Apply vendor patch.
Threat Intelligence Overview
NVD
CVE.org
EPSS
Vulnrichment
GitHub
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.
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