CVE-2026-66067

Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.

• https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.7 security-advisories@github.com
• https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.1 security-advisories@github.com
• https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-hwqx-2gfg-89qf security-advisories@github.com

The full cvelistV5 record. Download as CVE-2026-66067.json.

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "rabbitmq-server",
          "vendor": "rabbitmq",
          "versions": [
            {
              "status": "affected",
              "version": ">= 4.2.0, < 4.2.7"
            },
            {
              "status": "affected",
              "version": ">= 4.3.0, < 4.3.1"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 6,
            "baseSeverity": "MEDIUM",
            "privilegesRequired": "LOW",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "NONE"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-770",
              "description": "CWE-770: Allocation of Resources Without Limits or Throttling",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-23T20:12:00.076Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-hwqx-2gfg-89qf",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-hwqx-2gfg-89qf"
        },
        {
          "name": "https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.7",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.7"
        },
        {
          "name": "https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.1",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.1"
        }
      ],
      "source": {
        "advisory": "GHSA-hwqx-2gfg-89qf",
        "discovery": "UNKNOWN"
      },
      "title": "RabbitMQ: Stream protocol skips per vhost per user connection limits"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-66067",
    "datePublished": "2026-09-23T20:12:00.076Z",
    "dateReserved": "2026-07-23T23:25:28.897Z",
    "dateUpdated": "2026-09-23T20:12:00.076Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}