RabbitMQ: Web MQTT with PROXY Protocol enabled: a loopback-only user permission bypass

{
  "id": "f2127a6eb96e4dea597a39fd0427171080fc50dfef4a07d70aeb07e25980a2ed",
  "url": "https://osv.dev/vulnerability/BIT-rabbitmq-2026-67411",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "RabbitMQ: Web MQTT with PROXY Protocol enabled: a loopback-only user permission bypass",
    "summary": "RabbitMQ is a messaging and streaming broker. From 3.13.0 until 3.13.18, 4.0.23, 4.1.14, 4.2.9, and 4.3.3, native MQTT and MQTT over WebSocket behind a trusted PROXY Protocol frontend could lose the proxy-derived client address before the MQTT authentication path checked loopback_users, causing the frontend-to-broker address to be treated as loopback. An attacker who can reach the trusted frontend and has valid credentials for a loopback-restricted account can therefore bypass the source-address restriction; the issue does not bypass password authentication. This issue is fixed in versions 3.13.18, 4.0.23, 4.1.14, 4.2.9, and 4.3.3.",
    "evidence": "osv:BIT-rabbitmq-2026-67411",
    "products": [
      {
        "name": {
          "value": "rabbitmq",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "3.13.18",
            "evidence": "/affected/0/ranges"
          },
          {
            "value": "4.0.23",
            "evidence": "/affected/0/ranges"
          },
          {
            "value": "4.1.14",
            "evidence": "/affected/0/ranges"
          },
          {
            "value": "4.2.9",
            "evidence": "/affected/0/ranges"
          },
          {
            "value": "4.3.3",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "BIT-rabbitmq-2026-67411",
      "aliases": [
        "BIT-rabbitmq-2026-67411",
        "CVE-2026-67411",
        "GHSA-4r6f-9cpw-f6g6"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "3.13.0"
                },
                {
                  "fixed": "3.13.18"
                },
                {
                  "introduced": "4.0.0"
                },
                {
                  "fixed": "4.0.23"
                },
                {
                  "introduced": "4.1.0"
                },
                {
                  "fixed": "4.1.14"
                },
                {
                  "introduced": "4.2.0"
                },
                {
                  "fixed": "4.2.9"
                },
                {
                  "introduced": "4.3.0"
                },
                {
                  "fixed": "4.3.3"
                }
              ]
            }
          ],
          "package": {
            "name": "rabbitmq",
            "purl": "pkg:bitnami/rabbitmq",
            "ecosystem": "Bitnami"
          },
          "severity": [
            {
              "type": "CVSS_V3",
              "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N"
            }
          ],
          "database_specific": {
            "source": "https://github.com/bitnami/vulndb/tree/main/data/rabbitmq/BIT-rabbitmq-2026-67411.json"
          }
        }
      ],
      "modified": "2026-10-09T12:00:10.959339839Z",
      "provider": "osv",
      "references": [
        "https://github.com/rabbitmq/rabbitmq-server/commit/a7528314840c4f8dc9904684f9f97ffa7aac6349",
        "https://github.com/rabbitmq/rabbitmq-server/commit/edbead0eabbd65925d0dc914a22d6a29e155e646",
        "https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.9",
        "https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.3",
        "https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-4r6f-9cpw-f6g6",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-67411"
      ],
      "provider_metadata": {
        "cpes": [
          "cpe:2.3:a:vmware:rabbitmq:*:*:*:*:*:*:*:*"
        ],
        "severity": "High"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-67411",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/database_specific/severity"
  },
  "source_id": "core-osv",
  "document_id": 120680,
  "published_at": "2026-10-01T09:33:52.137+00:00"
}