CVE-2021-26919

Apache Druid allows users to read data from other database systems using JDBC. This functionality is to allow trusted users with the proper permissions to set up lookups or submit ingestion tasks. The MySQL JDBC driver supports certain properties, which, if left unmitigated, can allow an attacker to execute arbitrary code from a hacker-controlled malicious MySQL server within Druid server processes. This issue was addressed in Apache Druid 0.20.2

Source: CVE-2021-26919