{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "2.7.14"
              },
              {
                "introduced": "3.0.0"
              },
              {
                "fixed": "3.3.5"
              },
              {
                "introduced": "3.4.0"
              },
              {
                "fixed": "3.4.3"
              },
              {
                "introduced": "3.5.0"
              },
              {
                "fixed": "3.5.9"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "introduced": "c19f608838fdcb18fa81cab8a607afdaa5131a58"
            },
            {
              "introduced": "8be57f3b4bd0b1112cf871d9426beda6919b3bb7"
            },
            {
              "fixed": "defeee068496e3f6312e775c7de864f1b06388d4"
            },
            {
              "fixed": "f522a2f560c6e07d1d4b9a7957ed31bc57038af4"
            },
            {
              "fixed": "606bb6d6cf8fc02dc723ec468b5f753680da0993"
            },
            {
              "fixed": "df4ebe2c61293b7a79ab9dd440199544305d1f38"
            },
            {
              "fixed": "149ec6a626376214966c01f42d48be1b80d06056"
            },
            {
              "fixed": "d90b9872322c76b05a48219be66bff1d33102f8a"
            }
          ],
          "repo": "https://github.com/mariadb-corporation/mariadb-connector-j",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-g9jj-cgmh-9f38"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-522"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55856.json"
  },
  "details": "MariaDB Connector/J is used to connect applications developed in Java to MariaDB and MySQL databases. Prior to 2.7.14, 3.3.5, 3.4.3, and 3.5.9, when a Java application connects with sslMode=verify-full or sslMode=verify-ca, supplies a password, and does not configure serverSslCert or trustStore, Connector/J can accept an untrusted self-signed certificate through the fallbackToSystemTrustStore=true ephemeral trust manager and record its certFingerprint for later identity binding. The OK-packet and authentication-switch paths enforce the certificate fingerprint, but the initial-handshake path does not. HandshakeResponse.encode() can therefore build and send a mysql_clear_password response before checking certFingerprint != null \u0026\u0026 !isMitMProof(), sslMode, or whether the authentication plugin is resistant to a man-in-the-middle, and the initial path also bypasses restrictedAuth. An active man-in-the-middle or hostile server can present a self-signed certificate, claim to be MariaDB, select mysql_clear_password as the initial authentication plugin, and receive the full database password before the connection is rejected. This issue is fixed in versions 2.7.14, 3.3.5, 3.4.3, and 3.5.9.",
  "id": "CVE-2026-55856",
  "modified": "2026-09-10T03:30:18.047026655Z",
  "published": "2026-08-28T22:41:14.376Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.4.3"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.5.9"
    },
    {
      "type": "WEB",
      "url": "https://hackerone.com/reports/3777370"
    },
    {
      "type": "WEB",
      "url": "https://jira.mariadb.org/browse/CONJ-1325"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55856.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/mariadb-corporation/mariadb-connector-j/security/advisories/GHSA-g9jj-cgmh-9f38"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-55856"
    },
    {
      "type": "FIX",
      "url": "https://github.com/mariadb-corporation/mariadb-connector-j/commit/149ec6a626376214966c01f42d48be1b80d06056"
    },
    {
      "type": "FIX",
      "url": "https://github.com/mariadb-corporation/mariadb-connector-j/commit/d90b9872322c76b05a48219be66bff1d33102f8a"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "MariaDB Connector/J: Cleartext password disclosure to a MITM on the initial-handshake"
}