CVE-2026-55858

MEDIUM CVSS 3.1: 5.9 EPSS 0.34%
Updated Sep 01, 2026
MySQL
Parameter Value
CVSS 5.9 (MEDIUM)
Type CWE-838
Vendor MySQL
Public PoC No

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, the connector encodes and decodes protocol text and performs client-side escaping under the assumption that the connection character set is UTF-8. The server can report a mid-session change to character_set_client through OK-packet session-state tracking, including a change caused by SET NAMES, a stored routine or trigger, server configuration, or a hostile server.

If character_set_client changes to a non-UTF-8 value, the driver continues to read and write UTF-8 while the server interprets the same bytes under another encoding, causing silent data corruption and a client/server charset-confusion mismatch that can defeat byte-wise quoting or escaping. The fix accepts only utf8, utf8mb3, or utf8mb4 after initialization; any other value causes SQLException with SQLState 08000 and closes the connection. This issue is fixed in versions 2.7.14, 3.3.5, 3.4.3, and 3.5.9.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
High
Difficult to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
None
No data leak
Integrity
High
Complete data modification
Availability
None
No disruption

CVSS Vector v3.1

Weakness Type (CWE)

Vulnerable Products

mariadb-corporation:mariadb-connector-j

References 10

https://github.com/mariadb-corporation/mariadb-connector-j/security/advisories/…
https://github.com/mariadb-corporation/mariadb-connector-j/security/advisories/GHSA-xvr9-35cr-46v9
https://github.com/mariadb-corporation/mariadb-connector-j/commit/300716bef1e1d…
https://github.com/mariadb-corporation/mariadb-connector-j/commit/300716bef1e1d0370a41be7863b88aa2d55fbb69
https://github.com/mariadb-corporation/mariadb-connector-j/commit/7b3c69221b546…
https://github.com/mariadb-corporation/mariadb-connector-j/commit/7b3c69221b5463ee03472654040b3f6b9e5329c7
https://github.com/mariadb-corporation/mariadb-connector-j/commit/8cfd9df697372…
https://github.com/mariadb-corporation/mariadb-connector-j/commit/8cfd9df697372ad4ed09fe87a34b34babb6d43d6
https://github.com/mariadb-corporation/mariadb-connector-j/commit/c555c9b477521…
https://github.com/mariadb-corporation/mariadb-connector-j/commit/c555c9b477521be0c35c3a5461f9f46681553607
https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/2.7.14
https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/2.7.14
https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.3.5
https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.3.5
https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.4.3
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://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.5.9
https://jira.mariadb.org/browse/CONJ-1317
https://jira.mariadb.org/browse/CONJ-1317