MariaDB through 10.5.9 allows an application crash via certain long SELECT DISTINCT statements that improperly interact with storage-engine resource limitations for temporary data structures.
If, after successful installation of MantisBT through 2.5.2 on MySQL/MariaDB, the administrator does not remove the 'admin' directory (as recommended in the "Post-installation and upgrade tasks" section of the MantisBT Admin Guide), and the MySQL client has a local_infile setting enabled (in php.ini mysqli.allow_local_infile, or the MySQL client config file, depending on the PHP setup), an attacker may take advantage of MySQL's "connect file read" feature to remotely access files on the MantisBT server.