RabbitMQ: Incomplete fix for CVE-2026-44838: `escape_regex_char/1` does not escape `-`, leaving room for an MQTT topic permission bypass

{
  "id": "f7256ff194ae95c0ea865549073169f5b18223157ba309d15eaa0b47a0221242",
  "url": "https://osv.dev/vulnerability/BIT-rabbitmq-2026-67407",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "RabbitMQ: Incomplete fix for CVE-2026-44838: `escape_regex_char/1` does not escape `-`, leaving room for an MQTT topic permission bypass",
    "summary": "RabbitMQ is a messaging and streaming broker. From 4.0.0 until 4.3.3 and 4.2.9 and 4.1.14 and 4.0.23, Incomplete fix for CVE-2026-44838: escaperegexchar/1 does not escape -, leaving room for an MQTT topic permission bypass. the CVE-2026-44838 fix made expandtopicpermission/2 escape regex metacharacters in expanded topic-permission variables (escaperegex(V)), but escaperegexchar/1 escapes \\ ^ $ . | ? + ( ) [ ] { } and omits -. When a topic permission template places {clientid} inside a [...] character class A low-privileged authenticated MQTT user controlling its clientid can broaden topic authorization (read and write) when templates embed {clientid} in a [...] This issue is fixed in versions 4.3.3 and 4.2.9 and 4.1.14 and 4.0.23.",
    "evidence": "osv:BIT-rabbitmq-2026-67407",
    "products": [
      {
        "name": {
          "value": "rabbitmq",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "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-2026-67407",
      "aliases": [
        "BIT-rabbitmq-2026-67407",
        "CVE-2026-67407",
        "GHSA-q46v-hrvq-hp24"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "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": "4.3.2"
                },
                {
                  "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-2026-67407.json"
          }
        }
      ],
      "modified": "2026-10-17T09:15:02.391405996Z",
      "provider": "osv",
      "references": [
        "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-q46v-hrvq-hp24",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-67407"
      ],
      "provider_metadata": {
        "cpes": [
          "cpe:2.3:a:vmware:rabbitmq:*:*:*:*:*:*:*:*"
        ],
        "severity": "High"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-67407",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/database_specific/severity"
  },
  "source_id": "core-osv",
  "document_id": 352241,
  "published_at": "2026-10-01T09:33:46.619+00:00"
}