CVE-2021-26919: 
Java vulnerability analysis and mitigation

CVE-2021-26919 is a security vulnerability in Apache Druid that affects its JDBC functionality for reading data from other database systems. The vulnerability was discovered and assigned on February 9, 2021, and affects Apache Druid versions prior to 0.20.2. The issue specifically involves the MySQL JDBC driver's properties that, if not properly restricted, could be exploited (CVE Mitre).

The vulnerability exists in Apache Druid's JDBC functionality, which is designed to allow trusted users with proper permissions to set up lookups or submit ingestion tasks. The security flaw specifically relates to certain properties in the MySQL JDBC driver that, when left unmitigated, could be exploited to execute arbitrary code within Druid server processes through a malicious MySQL server (NVD).

If successfully exploited, this vulnerability allows authenticated users to execute arbitrary code from malicious MySQL database systems within the Druid server processes. The impact is significant as it affects the core functionality of data ingestion and lookup capabilities (Apache Mail).

The vulnerability requires high privileges to exploit, as only administrators can access the affected functionality. Despite the high privilege requirement, the attack complexity is considered low once the necessary access is obtained (Apache Discussion).

The vulnerability was addressed in Apache Druid version 0.20.2. The fix implements an allowlist for JDBC connection properties to prevent potential arbitrary code execution. Users are strongly advised to upgrade to this version or later to mitigate the vulnerability (CVE Mitre).