Mailu: Domain managers can allow themselves to spoof on other hosted domains they should not control

{
  "id": "6d3728c1e5138366662f66f53f1f43c00f01a8451682b2beaa3c4bcdfdf9343a",
  "url": "https://osv.dev/vulnerability/CVE-2026-86009",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Mailu: Domain managers can allow themselves to spoof on other hosted domains they should not control",
    "summary": "Mailu is a mail server distributed as a set of Docker images. Prior to f05aeb8322e2f61096af6b089d61ba6f40587d96, domain managers can enable spoofing for hosted domains they do not control. A potentially malicious domain administrator enables spoofing for another hosted domain and can send emails that are authenticated with DKIM/SPF for domains they should not be able to. This vulnerability is addressed by f05aeb8322e2f61096af6b089d61ba6f40587d96.",
    "evidence": "osv:CVE-2026-86009",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-86009",
      "aliases": [
        "CVE-2026-86009",
        "GHSA-crww-m82r-2wfm"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/mailu/mailu",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "f05aeb8322e2f61096af6b089d61ba6f40587d96"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "f05aeb8322e2f61096af6b089d61ba6f40587d96"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "f05aeb8322e2f61096af6b089d61ba6f40587d96"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "2024.06.1",
            "2024.06.0",
            "2.0.0",
            "1.9.10",
            "1.9.9",
            "1.9.8",
            "1.9.7",
            "1.9.6",
            "1.9.5",
            "1.9.4",
            "1.9.3",
            "1.9.2",
            "1.9.1",
            "1.9.0",
            "1.8-rc"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-86009.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:37.967811415Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/86xxx/CVE-2026-86009.json",
        "https://github.com/Mailu/Mailu/security/advisories/GHSA-crww-m82r-2wfm",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-86009",
        "https://github.com/Mailu/Mailu/issues/2686",
        "https://github.com/Mailu/Mailu/commit/f05aeb8322e2f61096af6b089d61ba6f40587d96",
        "https://github.com/Mailu/Mailu/pull/4072"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-285",
          "CWE-863"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/86xxx/CVE-2026-86009.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-86009",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 505414,
  "published_at": "2026-10-16T16:19:06.42+00:00"
}