CVE-2026-46355

HIGHPre-NVD 7.17.1—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 89% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
7.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.1Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
7.1
EG Score
7.1(medium)
EG Risk
32(Track)
EG Risk 32/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity71% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
11%
KEV
Not listed

Published

August 20, 2026

Last Modified

August 25, 2026

Advisory Details (3)

Auto-updated Aug 20, 2026
Patch available. Sources: github_commit, github_release, github.
github_release Patch Available

v3.0.23

Patch available: bigbluebutton/bigbluebutton v3.0.23

https://github.com/bigbluebutton/bigbluebutton/releases/tag/v3.0.23
github_commit

commit 972b04e474e1 (bigbluebutton/bigbluebutton)

Fix landed in bigbluebutton/bigbluebutton commit 972b04e474e1 — awaiting tagged release

https://github.com/bigbluebutton/bigbluebutton/commit/972b04e474e195cbd708b5b3f0485fe528a1a85b
github Patch Available

Unauthenticated Session Hijack via Exposed /bigbluebutton/api/handleJoinExistingUser · Advisory · bigbluebutton/bigbluebutton · GitHub

https://github.com/bigbluebutton/bigbluebutton/security/advisories/GHSA-38fw-2gq7-ccgr

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 12× in last 7d / 18× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-30 01:22 UTCEPSS rescore
  2. 2026-08-29 01:53 UTCEG score recompute
  3. 2026-08-28 21:41 UTCEPSS rescore
  4. 2026-08-27 14:59 UTCEG score recompute
  5. 2026-08-27 14:25 UTCEPSS rescore
  6. 2026-08-26 15:42 UTCEG score recompute
  7. 2026-08-26 14:46 UTCEPSS rescore
  8. 2026-08-25 16:26 UTCEG score recompute
  9. 2026-08-25 15:30 UTCEG score recompute
  10. 2026-08-25 13:49 UTCEPSS rescore
  11. 2026-08-24 19:13 UTCEG score recompute
  12. 2026-08-23 08:25 UTCEG score recompute
  13. 2026-08-23 00:19 UTCEPSS rescore
  14. 2026-08-22 09:13 UTCEG score recompute
  15. 2026-08-21 23:49 UTCEPSS rescore
  16. 2026-08-20 22:24 UTCEG score recompute
  17. 2026-08-20 21:42 UTCEG score recompute
  18. 2026-08-20 21:41 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-46355?
CVE-2026-46355 is a high vulnerability published on August 20, 2026. 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…
When was CVE-2026-46355 disclosed?
CVE-2026-46355 was first published in the National Vulnerability Database on August 20, 2026, with the most recent update on August 25, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-46355 actively exploited?
CVE-2026-46355 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 88.9% of all scored CVEs.
What is the CVSS score of CVE-2026-46355?
CVE-2026-46355 has a CVSS v3 base score of 7.1 (NVD).
How do I remediate CVE-2026-46355?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-46355, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-46355

Explore →

Is Your Infrastructure Affected by CVE-2026-46355?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs