CVE-2026-55489

MEDIUMPre-NVD 4.94.9
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

This medium-severity CVE scores 4.9 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3% (22nd percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
4.9EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 4.9Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

BigBlueButton is an open-source virtual classroom. Prior to 3.0.29, BigBlueButton presenters could submit a presentationId through /api/graphql that identified a presentation belonging to another meeting. akka-bbb-apps/src/main/scala/org/bigbluebutton/core/apps/presentationpod/RemovePresentationPubMsgHdlr.scala did not verify the presentation's meeting identifier before deletion, allowing a presenter who knew the identifier to delete another meeting's presentation and disrupt its availability. This issue is fixed in version 3.0.29.

CVSS v3
4.9
EG Score
4.9MEDIUMmedium confidence
EG Risk
22
EG Risk 22/100

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 (value × EchelonGraph’s weight)
Severity49% × 45%
The EG Score, 4.9 of 10.
Exploitation0.3% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.3%
EPSS %ILE
22nd
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

August 20, 2026

Last Modified

September 16, 2026

Advisory Details (3)

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

v3.0.29

Patch available: bigbluebutton/bigbluebutton v3.0.29

https://github.com/bigbluebutton/bigbluebutton/releases/tag/v3.0.29
GitHub commit

commit c9e93f9af07b (bigbluebutton/bigbluebutton)

Fix landed in bigbluebutton/bigbluebutton commit c9e93f9af07b — awaiting tagged release

https://github.com/bigbluebutton/bigbluebutton/commit/c9e93f9af07b9661e286d101b83cbccb891c551f
GitHub advisoryMentions a patch (unverified)

IDOR on BBB through /api/graphql via POST parameter "presentationId" leads to Authentication Bypass · Advisory · bigbluebutton/bigbluebutton · GitHub

https://github.com/bigbluebutton/bigbluebutton/security/advisories/GHSA-jxpq-r3h3-p75g

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 14× in last 7d / 54× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

  1. 2026-10-11 19:39 UTCEG score recompute
  2. 2026-10-11 16:54 UTCEG score recompute
  3. 2026-10-11 14:17 UTCEG score recompute
  4. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  5. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  6. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  7. 2026-10-09 08:14 UTCEG score recompute
  8. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  9. 2026-10-08 06:30 UTCEG score recompute
  10. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  11. 2026-10-07 07:19 UTCEG score recompute
  12. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  13. 2026-10-06 07:51 UTCEG score recompute
  14. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  15. 2026-10-05 04:56 UTCEG score recompute
  16. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  17. 2026-10-04 05:43 UTCEG score recompute
  18. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  19. 2026-10-03 06:35 UTCEG score recompute
  20. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  21. 2026-10-02 06:48 UTCEG score recompute
  22. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  23. 2026-10-01 07:15 UTCEG score recompute
  24. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  25. 2026-09-30 08:07 UTCEG score recompute
Show 66 more
  1. 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  2. 2026-09-29 01:52 UTCEG score recompute
  3. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  4. 2026-09-28 02:00 UTCEG score recompute
  5. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  6. 2026-09-27 02:52 UTCEG score recompute
  7. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  8. 2026-09-25 06:44 UTCEG score recompute
  9. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  10. 2026-09-24 07:36 UTCEG score recompute
  11. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  12. 2026-09-23 08:28 UTCEG score recompute
  13. 2026-09-22 09:20 UTCEG score recompute
  14. 2026-09-21 10:01 UTCEG score recompute
  15. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  16. 2026-09-20 10:53 UTCEG score recompute
  17. 2026-09-19 11:46 UTCEG score recompute
  18. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  19. 2026-09-18 12:18 UTCEG score recompute
  20. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  21. 2026-09-17 13:10 UTCEG score recompute
  22. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  23. 2026-09-16 13:46 UTCEG score recompute
  24. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  25. 2026-09-15 20:00 UTCEG score recompute
  26. 2026-09-15 03:11 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  27. 2026-09-13 21:44 UTCEG score recompute
  28. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  29. 2026-09-12 22:36 UTCEG score recompute
  30. 2026-09-11 23:28 UTCEG score recompute
  31. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  32. 2026-09-11 00:18 UTCEG score recompute
  33. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  34. 2026-09-09 01:52 UTCEG score recompute
  35. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  36. 2026-09-07 21:19 UTCEG score recompute
  37. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  38. 2026-09-06 22:10 UTCEG score recompute
  39. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  40. 2026-09-05 22:59 UTCEG score recompute
  41. 2026-09-04 23:51 UTCEG score recompute
  42. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  43. 2026-09-03 01:13 UTCEG score recompute
  44. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  45. 2026-09-02 02:02 UTCEG score recompute
  46. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  47. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  48. 2026-08-31 03:45 UTCEG score recompute
  49. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  50. 2026-08-30 04:38 UTCEG score recompute
  51. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  52. 2026-08-29 05:30 UTCEG score recompute
  53. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  54. 2026-08-27 07:09 UTCEG score recompute
  55. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  56. 2026-08-26 07:58 UTCEG score recompute
  57. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  58. 2026-08-25 08:50 UTCEG score recompute
  59. 2026-08-24 09:43 UTCEG score recompute
  60. 2026-08-22 11:27 UTCEG score recompute
  61. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  62. 2026-08-21 12:19 UTCEG score recompute
  63. 2026-08-21 11:30 UTCEG score recompute
  64. 2026-08-20 22:24 UTCEG score recompute
  65. 2026-08-20 21:42 UTCEG score recomputeFirst assessed: 4.9 MEDIUM
  66. 2026-08-20 21:41 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-55489?
CVE-2026-55489 is a medium-severity vulnerability; its CVE record was published on August 20, 2026. BigBlueButton is an open-source virtual classroom. Prior to 3.0.29, BigBlueButton presenters could submit a presentationId through /api/graphql that identified a presentation belonging to another meeting.…
When was the CVE record for CVE-2026-55489 published?
The CVE record for CVE-2026-55489 was published on August 20, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 16, 2026; the record at its source may have been updated since.
Is CVE-2026-55489 actively exploited?
CVE-2026-55489 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (22nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-55489?
CVE-2026-55489 has a CVSS base score of 4.9 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-55489?
A fix for CVE-2026-55489 is available: update to the fixed version the vendor names in its advisory.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-55489

Explore →

Is Your Infrastructure Affected by CVE-2026-55489?

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

Book a Demo →Browse All CVEs