RabbitMQ: Non-RFC-conformant cookie name when clearing the auth-mechanism preference

{
  "id": "e5d4d7c21f3a331e264b35e3b0337470f0b01ba16c21bb7ccb157e19c5afeb18",
  "url": "https://osv.dev/vulnerability/BIT-rabbitmq-2026-67234",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "RabbitMQ: Non-RFC-conformant cookie name when clearing the auth-mechanism preference",
    "summary": "RabbitMQ is a messaging and streaming broker. From 4.2.0 until 4.2.8 and 4.3.2, get_auth_mechanism/1 used term_to_binary/1 on the strict_auth_mechanism or preferred_auth_mechanism atom when clearing the corresponding cookie, producing a non-ASCII cookie name that violates RFC 6265 and can prevent the browser from deleting the preference. The issue is not directly exploitable for code execution or data exfiltration; its security relevance is limited to stale authentication-mechanism preferences persisting across logout and login cycles. This issue is fixed in versions 4.2.8 and 4.3.2.",
    "evidence": "osv:BIT-rabbitmq-2026-67234",
    "products": [
      {
        "name": {
          "value": "rabbitmq",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "4.2.8",
            "evidence": "/affected/0/ranges"
          },
          {
            "value": "4.3.2",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "BIT-rabbitmq-2026-67234",
      "aliases": [
        "BIT-rabbitmq-2026-67234",
        "CVE-2026-67234",
        "GHSA-q286-p3m9-j69f"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "4.2.0"
                },
                {
                  "fixed": "4.2.8"
                },
                {
                  "introduced": "4.3.0"
                },
                {
                  "fixed": "4.3.2"
                }
              ]
            }
          ],
          "package": {
            "name": "rabbitmq",
            "purl": "pkg:bitnami/rabbitmq",
            "ecosystem": "Bitnami"
          },
          "severity": [
            {
              "type": "CVSS_V3",
              "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N"
            }
          ],
          "database_specific": {
            "source": "https://github.com/bitnami/vulndb/tree/main/data/rabbitmq/BIT-rabbitmq-2026-67234.json"
          }
        }
      ],
      "modified": "2026-10-21T12:00:37.798755308Z",
      "provider": "osv",
      "references": [
        "https://github.com/rabbitmq/rabbitmq-server/commit/149cb59d618cefa83c6deb02dbbb1e8a7a2bc968",
        "https://github.com/rabbitmq/rabbitmq-server/commit/baac0aaf170efeb4f124ee36b8417274fa8dcc1a",
        "https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.8",
        "https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.2",
        "https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-q286-p3m9-j69f",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-67234"
      ],
      "provider_metadata": {
        "cpes": [
          "cpe:2.3:a:vmware:rabbitmq:*:*:*:*:*:*:*:*"
        ],
        "severity": "Medium"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-67234",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/database_specific/severity"
  },
  "source_id": "core-osv",
  "document_id": 393020,
  "published_at": "2026-10-01T09:33:28.5+00:00"
}