CVE-2026-46355Network attack vector

Participant impersonation via exposed controller action

Published Aug 20, 2026 · Updated Aug 25, 2026

Improper authentication in BigBlueButton before 3.0.23 allows remote attackers to impersonate active meeting participants. ApiController exposes handleJoinExistingUser as a routable action and accepts an existingUserID to retrieve and reuse that participant's server-side session. Exploitation requires the identifier of an active participant in the same meeting and grants that participant's meeting identity and permissions.

CVSS severity7.1
High
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authentication in BigBlueButton before 3.0.23 allows remote attackers to impersonate active meeting participants. ApiController exposes handleJoinExistingUser as a routable action and accepts an existingUserID to retrieve and reuse that participant's server-side session. Exploitation requires the identifier of an active participant in the same meeting and grants that participant's meeting identity and permissions.

The record

CVE
CVE-2026-46355
Published
Aug 20, 2026
Updated
Aug 25, 2026
Vendor
BigBlueButton Inc.
Product
BigBlueButton
Classifications
CWE-287, T1550.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=< 3.0.23

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

BigBlueButton Inc. · BigBlueButtonversion=< 3.0.23

Published CVSS scores

7.1GitHubCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-287Improper Authentication
T1550.004Use Alternate Authentication Material: Web Session Cookie

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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