CVE-2026-55857 MariaDB Connector/J: Cleartext Transmission of Sensitive Information and Insufficiently Protected Credentials
A man-in-the-middle attacker can steal user passwords transmitted in cleartext by the MariaDB Connector/J driver during PAM authentication over insecure connections.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-55857?
CVE-2026-55857 is a medium-severity vulnerability in mariadb-corporation mariadb-connector-j, published on 28 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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, PAM dialog authentication can be coerced into transmitting the account password over an insecure connection. The mysql_clear_password plugin is gated behind a secure transport, but the sibling PAM handler SendPamAuthPacketFactory, named dialog by the server, does not declare that requirement and inherits the default secure-required value false; older branches implement the same affected behavior in SendPamAuthPacket. A hostile or man-in-the-middle server can send an Authentication Switch Request for dialog over plain TCP, causing the driver to return the user's password in cleartext when sslMode=DISABLE and restrictedAuth=null, which is the default configuration. Properly verified TLS and local Unix sockets are not exposed to this transport vector. This issue is fixed in versions 2.7.14, 3.3.5, 3.4.3, and 3.5.9.
Which versions are affected by CVE-2026-55857?
8 open source packages ship an affected version, including org.mariadb.jdbc:mariadb-java-client.
| Package | Affected | Fixed in |
|---|---|---|
org.mariadb.jdbc:mariadb-java-client Maven | All versions | 2.7.14 |
org.mariadb.jdbc:mariadb-java-client Maven | All versions | 2.7.14 |
org.mariadb.jdbc:mariadb-java-client Maven | From 3.0.0 | 3.3.5 |
org.mariadb.jdbc:mariadb-java-client Maven | From 3.0.0 | 3.3.5 |
org.mariadb.jdbc:mariadb-java-client Maven | From 3.4.0 | 3.4.3 |
org.mariadb.jdbc:mariadb-java-client Maven | From 3.4.0 | 3.4.3 |
2 more packages
org.mariadb.jdbc:mariadb-java-client Maven | From 3.5.0 | 3.5.9 |
org.mariadb.jdbc:mariadb-java-client Maven | From 3.5.0 | 3.5.9 |
How do I fix CVE-2026-55857?
Upgrade org.mariadb.jdbc:mariadb-java-client to a fixed version for your release line: 2.7.14, 3.3.5, 3.4.3 or 3.5.9.
Is CVE-2026-55857 being exploited?
There is no known exploitation of CVE-2026-55857 in the wild and no public exploit code.
Sources
Also known as CLEANSTART-2026-DB67213, CLEANSTART-2026-DR90917, CLEANSTART-2026-HN65934, CLEANSTART-2026-UR21896, ECHO-bfa8-1e82-e7b7, GHSA-qxvw-fvwx-5cp7 and 15 more.