CVE-2026-66067

MEDIUMNVD 6.56.5
EchelonGraph scoreMEDIUM confidence

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

This medium-severity CVE scores 6.5 under NVD CVSS v3. EPSS exploit probability: 0.4% (38th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from NVD CVSS v3
Sources: EPSS, NVD CVSS v3

Also known asEUVD-2026-85633 (ENISA EUVD)Source: ENISA EUVD

6.5EG
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: 0.4%CVSS: 6.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

RabbitMQ is a messaging and streaming broker. Prior to versions 4.2.7 and 4.3.1, The stream open handler calls only check_vhost_access; it omits the node/vhost/user connection-limit checks that rabbit_reader performs for AMQP. A developer %% FIXME comment at the cited line explicitly acknowledges the gap. No compensating enforcement exists in connection tracking or elsewhere in rabbitmq_stream. An authenticated tenant can fully bypass operator-configured per-user and per-vhost connection caps by connecting via port 5552 instead of 5672. Preconditions include rabbitmq_stream plugin enabled Authenticated stream-protocol credentials Operator relies on per-user/per-vhost connection limits for tenant isolation. This issue is fixed in versions 4.2.7 and 4.3.1.

CVSS v3
6.5
EG Score
6.5MEDIUMmedium confidence
EG Risk
29
EG Risk 29/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity65% × 45%
Impact severity (EG Severity): CVSS 6.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.4% × 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
0.4%
EPSS %ILE
38th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (6.5): severity, escalated by confirmed exploitation. This CVE's 6.5 is its impact severity (EG Severity), not escalated.

EG Severity
6.5 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
EG Likelihood
0.4% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-03). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

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.

The score's inputs: 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

September 23, 2026

Last Modified

October 30, 2026

Advisory Details (3)

Auto-updated Sep 23, 2026
Patch available. Sources: github, github_release.
GitHub release Patch Available

RabbitMQ 4.3.1

Patch available: rabbitmq/rabbitmq-server v4.3.1

https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.1
GitHub release Patch Available

RabbitMQ 4.2.7

Patch available: rabbitmq/rabbitmq-server v4.2.7

https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.7
GitHub advisoryMentions a patch (unverified)

Stream protocol skips per vhost per user connection limits · Advisory · rabbitmq/rabbitmq-server · GitHub

https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-hwqx-2gfg-89qf

Vendor Advisories for CVE-2026-66067(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(1)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatrabbitmq-server4-3-main-4.3.6-1.hum12026-09-15redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(1 across 1 ecosystem)
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
rabbitmq-server4.0.5-10 ... 4.3.0-3 (11 versions)
  • every version up to 4.3.2-1: fixed in 4.3.2-1
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 35× 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 its CVE.org record (CNA or CISA ADP). 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). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

  1. 2026-11-12 16:34 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  2. 2026-11-11 16:40 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  3. 2026-11-10 16:45 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  4. 2026-11-09 16:36 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  5. 2026-11-08 16:40 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  6. 2026-11-07 16:39 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  7. 2026-11-06 16:39 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  8. 2026-11-05 16:38 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  9. 2026-11-04 16:36 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  10. 2026-11-04 01:58 UTCEchelonGraph re-scored
  11. 2026-11-04 01:58 UTCVendor advisory
  12. 2026-11-03 16:48 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  13. 2026-11-02 16:45 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  14. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  15. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  16. 2026-10-30 18:27 UTCEchelonGraph re-scored▲ 0.50
  17. 2026-10-30 18:27 UTCVendor advisory
  18. 2026-10-30 18:26 UTCNVD updateCVSS v3 → 6.5
  19. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  20. 2026-10-30 07:55 UTCOSV refresh
  21. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  22. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  23. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  24. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  25. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.4% · 28th percentile
Show 72 more
  1. 2026-10-25 14:11 UTCEchelonGraph re-scored
  2. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  3. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  4. 2026-10-22 19:37 UTCEchelonGraph re-scored
  5. 2026-10-22 19:37 UTCVendor advisory
  6. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  7. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  8. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  9. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  10. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  11. 2026-10-18 03:21 UTCEchelonGraph re-scored
  12. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  13. 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  14. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  15. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  16. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  17. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  18. 2026-10-12 15:46 UTCEchelonGraph re-scored
  19. 2026-10-12 03:50 UTCVendor advisory
  20. 2026-10-11 19:31 UTCEchelonGraph re-scored
  21. 2026-10-11 16:46 UTCEchelonGraph re-scored
  22. 2026-10-11 14:07 UTCEchelonGraph re-scored
  23. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  24. 2026-10-11 00:42 UTCEchelonGraph re-scored
  25. 2026-10-11 00:42 UTCVendor advisory
  26. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  27. 2026-10-09 22:23 UTCEchelonGraph re-scored
  28. 2026-10-09 22:23 UTCVendor advisory
  29. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  30. 2026-10-08 20:09 UTCEchelonGraph re-scored
  31. 2026-10-08 20:09 UTCVendor advisory
  32. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  33. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  34. 2026-10-07 17:54 UTCVendor advisory
  35. 2026-10-06 15:40 UTCEchelonGraph re-scored
  36. 2026-10-06 15:40 UTCVendor advisory
  37. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  38. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  39. 2026-10-05 13:27 UTCEchelonGraph re-scored
  40. 2026-10-05 13:27 UTCVendor advisory
  41. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  42. 2026-10-04 11:14 UTCEchelonGraph re-scored
  43. 2026-10-04 11:14 UTCVendor advisory
  44. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  45. 2026-10-03 09:01 UTCEchelonGraph re-scored
  46. 2026-10-03 09:01 UTCVendor advisory
  47. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  48. 2026-10-02 06:45 UTCEchelonGraph re-scored
  49. 2026-10-02 06:45 UTCVendor advisory
  50. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  51. 2026-10-01 04:32 UTCEchelonGraph re-scored
  52. 2026-10-01 04:32 UTCVendor advisory
  53. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  54. 2026-09-30 02:19 UTCEchelonGraph re-scored
  55. 2026-09-30 02:19 UTCVendor advisory
  56. 2026-09-29 00:07 UTCEchelonGraph re-scored
  57. 2026-09-29 00:06 UTCVendor advisory
  58. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  59. 2026-09-27 21:54 UTCEchelonGraph re-scored
  60. 2026-09-27 21:54 UTCVendor advisory
  61. 2026-09-26 19:37 UTCEchelonGraph re-scored
  62. 2026-09-26 19:37 UTCVendor advisory
  63. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  64. 2026-09-25 17:22 UTCVendor advisory
  65. 2026-09-24 15:08 UTCVendor advisory
  66. 2026-09-24 14:34 UTCEchelonGraph re-scored
  67. 2026-09-24 14:34 UTCVendor advisory
  68. 2026-09-24 14:17 UTCEchelonGraph re-scored
  69. 2026-09-24 14:17 UTCVendor advisory
  70. 2026-09-23 21:22 UTCEchelonGraph re-scored
  71. 2026-09-23 20:24 UTCEchelonGraph re-scoredFirst assessed: 6.0 MEDIUM
  72. 2026-09-23 20:23 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-66067?
CVE-2026-66067 is a medium-severity vulnerability; its CVE record was published on September 23, 2026. RabbitMQ is a messaging and streaming broker. Prior to versions 4.2.7 and 4.3.1, The stream open handler calls only check_vhost_access; it omits the node/vhost/user connection-limit checks that rabbit_reader performs for AMQP. A developer %% FIXME comment at the cited line explicitly acknowledges…
When was the CVE record for CVE-2026-66067 published?
The CVE record for CVE-2026-66067 was published on September 23, 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 October 30, 2026; the record at its source may have been updated since.
Is CVE-2026-66067 actively exploited?
CVE-2026-66067 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (38th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-66067?
CVE-2026-66067 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-66067?
A fix for CVE-2026-66067 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-66067 are linked in the Vendor Advisories panel on this page.

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