{"id":"CVE-2026-55857","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-55857","summary":"org.mariadb.jdbc:mariadb-java-client has Cleartext Transmission of Sensitive Information and Insufficiently Protected Credentials","details":"### Summary\n\nWhen PAM (dialog) authentication is used, the connector can be coerced into sending the account password in cleartext over an insecure connection. A hostile or man-in-the-middle server can trigger this with the default configuration, disclosing the user's password.\n\n### Details\n\nThe mysql_clear_password plugin is gated behind a secure connection: the driver refuses to transmit the password in cleartext over plain TCP. The sibling PAM plugin handler (SendPamAuthPacketFactory, server-side plugin name dialog) did not override that gate and inherited the default value false, so it was not subject to the same secure-transport requirement.\n\nAs a result, a hostile or man-in-the-middle server can issue an Authentication Switch Request for the dialog plugin over plain TCP, and the driver responds with the user's password in cleartext. With the default configuration (sslMode=DISABLE, restrictedAuth=null) this is reachable with no non-default options.\n\n### Am I affected?\n\nYou are affected if all of the following hold:\n\n\n* You use mariadb Connector/J at a version below the patched release(s).\n* Connections can occur over an insecure transport — i.e. plain TCP (sslMode=DISABLE), or a TLS mode that establishes server identity only via self-signed-certificate fingerprint validation.\n* An attacker can occupy an on-path (MITM) position, or otherwise cause the client to connect to a server they control, and present an Authentication Switch Request for the dialog plugin.\n\nConnections over properly verified TLS or a local Unix socket are not exposed to this vector.\n\n### Impact\n\nDisclosure of the authenticating account's password in cleartext to an on-path or hostile server. The captured credentials can then be reused to authenticate to the database.\n\n### Patches\n\nFixed in 2.7.14, 3.3.5, 3.4.3, and 3.5.9. Upgrade to the patched release on your branch (3.5.x → 3.5.9, 3.4.x → 3.4.3, 3.0/3.1/3.2/3.3.x → 3.3.5, 2.x → 2.7.14). PAM (dialog) is now treated exactly like mysql_clear_password: it may only run over a secure transport. SendPamAuthPacketFactory overrides the secure-required flag to true, and the authentication dispatcher permits a secure-required plugin only when the connection is TLS or a local Unix socket. The pre-existing check that blocks non-MITM-proof plugins when server identity relies solely on self-signed-certificate fingerprint validation continues to apply. Net effect: PAM is allowed over TLS or a Unix socket, and rejected over plain TCP or fingerprint-only connections.\n\n### Workarounds\n\nIf you cannot upgrade immediately:\n\n* Connect over verified TLS (set sslMode=verify-full) so a man-in-the-middle cannot impersonate the server, or use a local Unix socket.\n* Restrict the permitted authentication plugins via restrictedAuth so dialog cannot be negotiated over an insecure transport.\n\n\n### Credit\n\nReported by Yalguun Tumenkhuu ([@fg0x0](https://github.com/fg0x0/)).","published":"2026-08-28T22:45:01Z","modified":"2026-08-28T23:00:08.191886243Z","cvss":{"score":5.9,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Maven","name":"org.mariadb.jdbc:mariadb-java-client","fixedVersion":"2.7.14"},{"ecosystem":"Maven","name":"org.mariadb.jdbc:mariadb-java-client","fixedVersion":"3.3.5"},{"ecosystem":"Maven","name":"org.mariadb.jdbc:mariadb-java-client","fixedVersion":"3.4.3"},{"ecosystem":"Maven","name":"org.mariadb.jdbc:mariadb-java-client","fixedVersion":"3.5.9"}],"fix":{"url":"https://github.com/mariadb-corporation/mariadb-connector-j/commit/a8599ab1cbe4b8818ea945bf56a4e012c302b388","label":"mariadb-corporation/mariadb-connector-j@a8599ab"},"references":[{"type":"WEB","url":"https://github.com/mariadb-corporation/mariadb-connector-j/security/advisories/GHSA-qxvw-fvwx-5cp7"},{"type":"WEB","url":"https://github.com/mariadb-corporation/mariadb-connector-j/commit/a8599ab1cbe4b8818ea945bf56a4e012c302b388"},{"type":"WEB","url":"https://github.com/mariadb-corporation/mariadb-connector-j/commit/f4a727c764d1cf48fd0c3d5e301dfa92503e0a58"},{"type":"PACKAGE","url":"https://github.com/mariadb-corporation/mariadb-connector-j"},{"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://jira.mariadb.org/browse/CONJ-1320"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-28T23:00:08.191886243Z"}}