FKIE_CVE-2026-126611

Vulnerability from fkie_nvd - Published: 2026-11-11 09:17 - Updated: 2026-11-12 19:05
Summary
Progressive Robot hMailServer 6.3.4 through 6.3.7, with a MySQL or MariaDB database, TlsMode=verify-full and no TlsCaFile, does not verify the database server's certificate's issuer or name when the connection is one that MariaDB Connector/C treats as local - Server= set to 127.0.0.1, ::1 or localhost (on Linux a Unix socket), to . on Windows (a named pipe), or to a comma-separated list of servers that holds such an element - which allows a local attacker who can stand in for the database server, for example by listening on its port while it is stopped or restarting, to receive the database sign-in, the password included, and to read and modify the traffic between hMailServer and its database. hMailServer applied verify-full by turning the client's certificate verification on without a CA file, but MariaDB Connector/C 3.4.1 and later, on a connection they treat as local and with no CA file, accept any certificate within its validity period that is self-signed or sent with its own root, for any name (Connector/C 3.4.2 to 3.4.10 also one whose issuer they cannot find), so the client accepted the certificate an impostor made, asked no proof of the password and allowed a switch to an authentication method that sends the password unhashed, while hmailserver --check-database said the certificate had been checked against the system's trust store and the application log that it had been checked. The Windows builds bundle Connector/C 3.4.9 (6.3.4 to 6.3.6) and 3.4.11 (6.3.7); on Linux the distribution's client is used, and Connector/C 3.3 and 3.4.0 and Oracle's MySQL client are not affected. The configuration is not the default: TlsMode defaults to prefer, which checks no certificate.
Impacted products
Vendor Product Version

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "hMailServer",
          "repo": "https://gitlab.com/hmailserver/hmailserver",
          "vendor": "Progressive Robot Ltd",
          "versions": [
            {
              "lessThanOrEqual": "6.3.7",
              "status": "affected",
              "version": "6.3.4",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "cve@gitlab.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Progressive Robot hMailServer 6.3.4 through 6.3.7, with a MySQL or MariaDB database, TlsMode=verify-full and no TlsCaFile, does not verify the database server\u0027s certificate\u0027s issuer or name when the connection is one that MariaDB Connector/C treats as local - Server= set to 127.0.0.1, ::1 or localhost (on Linux a Unix socket), to . on Windows (a named pipe), or to a comma-separated list of servers that holds such an element - which allows a local attacker who can stand in for the database server, for example by listening on its port while it is stopped or restarting, to receive the database sign-in, the password included, and to read and modify the traffic between hMailServer and its database. hMailServer applied verify-full by turning the client\u0027s certificate verification on without a CA file, but MariaDB Connector/C 3.4.1 and later, on a connection they treat as local and with no CA file, accept any certificate within its validity period that is self-signed or sent with its own root, for any name (Connector/C 3.4.2 to 3.4.10 also one whose issuer they cannot find), so the client accepted the certificate an impostor made, asked no proof of the password and allowed a switch to an authentication method that sends the password unhashed, while hmailserver --check-database said the certificate had been checked against the system\u0027s trust store and the application log that it had been checked. The Windows builds bundle Connector/C 3.4.9 (6.3.4 to 6.3.6) and 3.4.11 (6.3.7); on Linux the distribution\u0027s client is used, and Connector/C 3.3 and 3.4.0 and Oracle\u0027s MySQL client are not affected. The configuration is not the default: TlsMode defaults to prefer, which checks no certificate."
    }
  ],
  "id": "CVE-2026-126611",
  "lastModified": "2026-11-12T19:05:35.013",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.0,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.0,
        "impactScore": 5.9,
        "source": "cve@gitlab.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-11-11T09:17:12.973",
  "references": [
    {
      "source": "cve@gitlab.com",
      "url": "https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.8"
    },
    {
      "source": "cve@gitlab.com",
      "url": "https://gitlab.com/hmailserver/hmailserver/-/work_items/113"
    }
  ],
  "sourceIdentifier": "cve@gitlab.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-295"
        }
      ],
      "source": "cve@gitlab.com",
      "type": "Primary"
    }
  ]
}



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