SQL Data Source Plugin: OOM DoS via $__timeGroup macro

An authenticated user with permission to query a SQL data source can bypass the fix for CVE-2026-33375 by injecting the timeGroup macro through a WHERE clause, which Grafana's regex-based macro parsing does not reject. Evaluating the injected macro causes uncontrolled memory consumption that can terminate the Grafana server process, resulting in a denial of service. The Microsoft SQL Server, PostgreSQL, and MySQL data sources are affected.