Vulnerability · Published Aug 28, 2026 · Assigned by GitHub_M
CVE-2026-55856MariaDB Connector/J: Cleartext password disclosure to a MITM on the initial-handshake
Medium 5.9
In plain English
A medium-severity security flaw in mariadb-connector-j from mariadb-corporation. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 39% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Maven | org.mariadb.jdbc:mariadb-java-client | 2.7.14 | GHSA-g9jj-cgmh-9f38 |
| Maven | org.mariadb.jdbc:mariadb-java-client | 3.3.5 | GHSA-g9jj-cgmh-9f38 |
| Maven | org.mariadb.jdbc:mariadb-java-client | 3.4.3 | GHSA-g9jj-cgmh-9f38 |
| Maven | org.mariadb.jdbc:mariadb-java-client | 3.5.9 | GHSA-g9jj-cgmh-9f38 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| mariadb-corporation | mariadb-connector-j | < 2.7.14>= 3.0.0, < 3.3.5>= 3.4.0, < 3.4.3>= 3.5.0, < 3.5.9 |
Weakness: CWE-522 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
References
- https://github.com/mariadb-corporation/mariadb-connector-j/security/advisories/GHSA-g9jj-cgmh-9f38 x_refsource_CONFIRM
- https://github.com/mariadb-corporation/mariadb-connector-j/commit/149ec6a626376214966c01f42d48be1b80d06056 x_refsource_MISC
- https://github.com/mariadb-corporation/mariadb-connector-j/commit/d90b9872322c76b05a48219be66bff1d33102f8a x_refsource_MISC
- https://hackerone.com/reports/3777370 x_refsource_MISC
- https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.4.3 x_refsource_MISC
- https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.5.9 x_refsource_MISC
- https://jira.mariadb.org/browse/CONJ-1325 x_refsource_MISC