{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "1.26.1"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "193b6e7767889511cfa8e933908ea5e6a1077a1f"
            },
            {
              "fixed": "a326649e16eee1fa6ff74c87b103eb8eb601b5cf"
            }
          ],
          "repo": "https://github.com/halfgaar/flashmq",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-2789-vfcg-5922"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-369"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42209.json"
  },
  "details": "FlashMQ is a MQTT broker/server, designed for multi-CPU environments. Prior to version 1.26.1, a remote client with retained publish permission can crash the FlashMQ broker when both set_retained_message_defer_timeout and set_retained_message_defer_timeout_spread are configured to non-default values, resulting in denial of service. If anonymous retained publishing is allowed, no authentication is required; otherwise, the attacker needs the corresponding publish permission. This issue has been patched in version 1.26.1.",
  "id": "CVE-2026-42209",
  "modified": "2026-07-15T01:49:12.167168458Z",
  "published": "2026-05-08T21:40:43.284Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/halfgaar/FlashMQ/releases/tag/v1.26.1"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42209.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/halfgaar/FlashMQ/security/advisories/GHSA-2789-vfcg-5922"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-42209"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/halfgaar/FlashMQ/issues/167"
    },
    {
      "type": "FIX",
      "url": "https://github.com/halfgaar/FlashMQ/commit/193b6e7767889511cfa8e933908ea5e6a1077a1f"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "FlashMQ: Division by zero crash when using non-default deferred retained message setting"
}