{"id":"CVE-2026-55856","state":"PUBLISHED","title":"MariaDB Connector/J: Cleartext password disclosure to a MITM on the initial-handshake","description":"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 && !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.","publishedAt":"2026-08-28T22:41:14.376Z","updatedAt":"2026-08-31T18:37:36.732Z","severity":{"score":5.9,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["mariadb-corporation mariadb-connector-j"],"affected":[{"vendor":"mariadb-corporation","product":"mariadb-connector-j","versions":[{"version":"< 2.7.14","status":"affected"},{"version":">= 3.0.0, < 3.3.5","status":"affected"},{"version":">= 3.4.0, < 3.4.3","status":"affected"},{"version":">= 3.5.0, < 3.5.9","status":"affected"}]}],"references":["https://github.com/mariadb-corporation/mariadb-connector-j/security/advisories/GHSA-g9jj-cgmh-9f38","https://github.com/mariadb-corporation/mariadb-connector-j/commit/149ec6a626376214966c01f42d48be1b80d06056","https://github.com/mariadb-corporation/mariadb-connector-j/commit/d90b9872322c76b05a48219be66bff1d33102f8a","https://hackerone.com/reports/3777370","https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.4.3","https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.5.9","https://jira.mariadb.org/browse/CONJ-1325"],"weaknesses":["CWE-522"],"ingestedAt":"2026-10-29T20:12:24.861Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/55xxx/CVE-2026-55856.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-55856","state":"PUBLISHED","datePublished":"2026-08-28T22:41:14.376Z","dateUpdated":"2026-08-31T18:37:36.732Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-17T16:44:40.995Z"},"containers":{"cna":{"title":"MariaDB Connector/J: Cleartext password disclosure to a MITM on the initial-handshake","descriptions":[{"lang":"en","value":"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 && !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."}],"affected":[{"vendor":"mariadb-corporation","product":"mariadb-connector-j","versions":[{"version":"< 2.7.14","status":"affected"},{"version":">= 3.0.0, < 3.3.5","status":"affected"},{"version":">= 3.4.0, < 3.4.3","status":"affected"},{"version":">= 3.5.0, < 3.5.9","status":"affected"}]}],"references":[{"url":"https://github.com/mariadb-corporation/mariadb-connector-j/security/advisories/GHSA-g9jj-cgmh-9f38","name":"https://github.com/mariadb-corporation/mariadb-connector-j/security/advisories/GHSA-g9jj-cgmh-9f38","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/mariadb-corporation/mariadb-connector-j/commit/149ec6a626376214966c01f42d48be1b80d06056","name":"https://github.com/mariadb-corporation/mariadb-connector-j/commit/149ec6a626376214966c01f42d48be1b80d06056","tags":["x_refsource_MISC"]},{"url":"https://github.com/mariadb-corporation/mariadb-connector-j/commit/d90b9872322c76b05a48219be66bff1d33102f8a","name":"https://github.com/mariadb-corporation/mariadb-connector-j/commit/d90b9872322c76b05a48219be66bff1d33102f8a","tags":["x_refsource_MISC"]},{"url":"https://hackerone.com/reports/3777370","name":"https://hackerone.com/reports/3777370","tags":["x_refsource_MISC"]},{"url":"https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.4.3","name":"https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.4.3","tags":["x_refsource_MISC"]},{"url":"https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.5.9","name":"https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.5.9","tags":["x_refsource_MISC"]},{"url":"https://jira.mariadb.org/browse/CONJ-1325","name":"https://jira.mariadb.org/browse/CONJ-1325","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":5.9,"baseSeverity":"MEDIUM","confidentialityImpact":"HIGH","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-522","lang":"en","description":"CWE-522: Insufficiently Protected Credentials","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-08-28T22:41:14.376Z"},"source":{"advisory":"GHSA-g9jj-cgmh-9f38","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-31T18:37:25.396891Z","id":"CVE-2026-55856","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-31T18:37:36.732Z"}}]}}}