MariaDB Connector/C: libmariadb allowed cleartext password leakage on TLS hostname verification failure

MariaDB Connector/C is a C and C++ client library for connecting applications to MariaDB and MySQL databases. From 3.4.1 until 3.4.10, the MariaDB Connector/C libmariadb Zero-Configuration SSL authentication-switch logic checked certificate trust failure but did not reject a TLS hostname verification mismatch before selecting a non-hashing authentication plugin. An active man-in-the-middle attacker with a valid certificate for another hostname could request mysql_clear_password and obtain the database password inside the attacker-controlled TLS connection. Other MariaDB connectors are not affected. This issue is fixed in version 3.4.10.

Source published

9 Oct 2026 17:25:45 UTC

Source modified

9 Oct 2026 17:59:15 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

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CVSS 3.1 · 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N