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TI-2026-34072 Aliases CVE-2026-46355

BigBlueButton: Unauthenticated Session Hijack via Exposed /bigbluebutton/api/handleJoinExistingUser

Priority LOW 31CWE-287Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
Low · High · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-287.

Summary

BigBlueButton is an open-source virtual classroom. Prior to 3.0.23, BigBlueButton exposed /bigbluebutton/api/handleJoinExistingUser through bigbluebutton-web/grails-app/controllers/org/bigbluebutton/web/controllers/ApiController.groovy. A requester able to supply an existingUserID for an active participant could reuse that participant's session and impersonate the participant in the same meeting because handleJoinExistingUser was a routable controller action rather than a private helper. This issue is fixed in version 3.0.23.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0037 31st percentileScored 2026-11-07
Fix Fixed bigbluebutton (bigbluebutton): 3.0.23

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
bigbluebuttonbigbluebuttonbefore 3.0.233.0.23Patch availableCNA
  • bigbluebutton Vendorbigbluebutton Affected before 3.0.23 Fixed in 3.0.23 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:bigbluebutton:bigbluebutton:*:*:*:*:*:*:*:*——bigbluebutton
  • cpe:2.3:a:bigbluebutton:bigbluebutton:*:*:*:*:*:*:*:* Versions — — ·bigbluebutton

Remediation

  • Fix · CNA bigbluebutton (bigbluebutton) Fixed in 3.0.23

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-46355

References

Other 3

  • TI-2026-21873 BigBlueButton: Exposed ClamAV port enables Denial of Service CVSS 3.1HIGH 8.2
  • TI-2025-38047 BigBlueButton vulnerable to Chat DoS via invalid reactionEmojiId CVSS 3.1HIGH 7.5
  • TI-2025-38046 BigBlueButton vulnerable to DoS via PollSubmitVote GraphQL mutation CVSS 3.1HIGH 7.5
  • TI-2022-13109 Cross site scripting in username that will trigger by sending chat CVSS 3.1MEDIUM 6.5
  • TI-2020-09954 BigBlueButton before 2.2.6 allows remote attackers to read arbitrary files because the… CVSS 3.1CRITICAL 9.8
  • TI-2022-16454 BigBlueButton Greenlight Open Redirect vulnerability CVSS 3.1CRITICAL 9.1
See all 66 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences