RabbitMQ: Admin-only atom exhaustion: PUT /api/users tags list

{
  "id": "61cbb5bbf42a96f939d8264cd8635a88fdfe7dee16942eecd775d715bce366e8",
  "url": "https://osv.dev/vulnerability/CVE-2026-67226",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "RabbitMQ: Admin-only atom exhaustion: PUT /api/users tags list",
    "summary": "RabbitMQ is a messaging and streaming broker. From 4.0.0 until 4.0.22 and 4.1.14 and 4.2.7, Admin-only atom exhaustion: PUT /api/users tags list. settags/2 maps rabbitdatacoercion:toatom/1 over the user's tags list. The 20 MB management body limit fits ~3-4M short tag strings. An administrator can crash the node in a single request by creating a user (or importing definitions) with ~1M unique tag administrator. This issue is fixed in versions 4.0.22 and 4.1.14 and 4.2.7.",
    "evidence": "osv:CVE-2026-67226",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-67226",
      "aliases": [
        "BIT-rabbitmq-2026-67226",
        "CVE-2026-67226",
        "GHSA-34c7-r8w9-5wv8"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/rabbitmq/rabbitmq-server",
              "type": "GIT",
              "events": [
                {
                  "introduced": "95c501fbad76c66156346cf364d158d6e30aa4d9"
                },
                {
                  "fixed": "b15fd2a3e5465cb6ed403d5a774ef61b1a391b89"
                },
                {
                  "fixed": "86601c5a6d1c7e41060e3dbd165c88bdc91266ee"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:broadcom:rabbitmq_server:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "4.2.0"
                      },
                      {
                        "fixed": "4.2.7"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "86601c5a6d1c7e41060e3dbd165c88bdc91266ee"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "b15fd2a3e5465cb6ed403d5a774ef61b1a391b89"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v4.2.7"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v4.2.6",
            "v4.2.5",
            "v4.2.4",
            "v4.2.3",
            "v4.2.2",
            "v4.2.1",
            "v4.2.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-67226.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:33.783166632Z",
      "provider": "osv",
      "references": [
        "https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.7",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/67xxx/CVE-2026-67226.json",
        "https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-34c7-r8w9-5wv8",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-67226",
        "https://github.com/rabbitmq/rabbitmq-server/commit/86601c5a6d1c7e41060e3dbd165c88bdc91266ee"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-400"
        ],
        "cna_assigner": "GitHub_M",
        "unresolved_ranges": [
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "4.0.0"
                  },
                  {
                    "fixed": "4.0.22"
                  },
                  {
                    "introduced": "4.1.0"
                  },
                  {
                    "fixed": "4.1.14"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StringRangeExpression"
              }
            ]
          }
        ],
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/67xxx/CVE-2026-67226.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-67226",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 501096,
  "published_at": "2026-09-25T16:29:13.662+00:00"
}