A use-after-free vulnerability was found in MariaDB's SYS_REFCURSOR handling during FETCH operations. An authenticated, low-privileged SQL user can trigger a use-after-free condition that potentially allows control over a virtual function call. When chained with a separate information-disclosure vulnerability, this can be used to modify Security_context::master_access to obtain FILE privileges and subsequently achieve operating-system command execution through UDF loading.

The researcher reports successful exploitation against MariaDB 13.0.1-rc with ASLR, PIE, and Full RELRO enabled.

Reference: https://hackerone.com/reports/3856148