CVE-2026-119278: MariaDB Connector/J: Rogue server can crash the client during caching_sha2_password authentication

Vulnerability summary

CVE-2026-119278 is a medium (CVSS 5.9) Improper Validation of Array Index vulnerability in mariadb-corporation mariadb-connector-j. EPSS estimates a 0.36% chance of exploitation in the next 30 days, higher than 30.3% of scored vulnerabilities.

Timeline

1. 29-10-2026
   PublishedVulnerability first disclosed.
2. 30-10-2026
   Last modifiedVulnerability information updated.

Description

MariaDB Connector/J is used to connect applications developed in Java to MariaDB and MySQL databases. From 3.0.0 until 3.3.7 and 3.4.5, during caching_sha2_password authentication, the authentication-more-data response was treated as a length-encoded byte array, memory was allocated from the server-declared length, and authResult[0] was accessed without ensuring a byte existed. A malicious or compromised server, or a machine-in-the-middle attacker, could declare a very large length or send an empty response before any password was transmitted. The malformed packet could cause excessive allocation or an unchecked ArrayIndexOutOfBoundsException escaping from DriverManager.getConnection(). This issue is fixed in versions 3.3.7 and 3.4.5.

• CWE-129Improper Validation of Array IndexThe product uses untrusted input when calculating or using an array index, but the product does not validate or incorrectly validates the index to ensure the index references a valid position within the array.
• CWE-789Memory Allocation with Excessive Size ValueThe product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated.