Logstash Improper Certificate Validation in TCP output

{
  "id": "f34a2302c0b2b190f824b975266d8e90ced2da86ae085701c8e21d50b5bf5ce2",
  "url": "https://osv.dev/vulnerability/CVE-2025-37730",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Logstash Improper Certificate Validation in TCP output",
    "summary": "Improper certificate validation in Logstash's TCP output could lead to a man-in-the-middle (MitM) attack in “client” mode, as hostname verification in TCP output was not being performed when the ssl_verification_mode => full was set.",
    "evidence": "osv:CVE-2025-37730",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2025-37730",
      "aliases": [
        "BIT-logstash-2025-37730",
        "CVE-2025-37730"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/elastic/logstash",
              "type": "GIT",
              "events": [
                {
                  "introduced": "737f0617b0f41a50b735f2e59fd6dca67519c414"
                },
                {
                  "fixed": "03939becb3a1a37debf605569aebea0dff9bb2f3"
                },
                {
                  "introduced": "9e3be9602a620af998d9bfdbbb632e06ad082c82"
                },
                {
                  "fixed": "4f9dfc74ddac310aefb1db8f0766cf47127de3d4"
                },
                {
                  "introduced": "f15ae9fbb067e491795deeed285d44c784f997da"
                },
                {
                  "fixed": "4e850d791be668438b0d19f729fa734d4bc7657b"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "8.0.0"
                      },
                      {
                        "fixed": "8.17.6"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "introduced": "8.18.0"
                      },
                      {
                        "fixed": "8.18.1"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "introduced": "9.0.0"
                      },
                      {
                        "fixed": "9.0.1"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v8.18.0",
            "v9.0.0-rc1",
            "v9.0.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-37730.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:25.676705496Z",
      "provider": "osv",
      "references": [
        "https://discuss.elastic.co/t/logstash-8-17-6-8-18-1-and-9-0-1-security-update-esa-2025-08/377869",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/37xxx/CVE-2025-37730.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-37730",
        "https://github.com/elastic/logstash"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-295"
        ],
        "cna_assigner": "elastic",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/37xxx/CVE-2025-37730.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-37730",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 492401,
  "published_at": "2025-05-06T17:29:07.189+00:00"
}