The vulnerability exists in the /api/v2/dagReports endpoint, which was handled by the get_dag_reports function in airflow.api_fastapi.core_api.routes.public.dag_report. The analysis of the patch 828aaa0b1d95caf90612a648867c17aec7e87874 shows that this endpoint and its corresponding handler function were completely removed. The function's implementation shows that it used DagBag(fullpath) to load DAGs from a user-provided subdirectory. The DagBag class executes Python files to parse DAGs, creating a remote code execution vulnerability. The commit message explicitly states that this behavior violates Airflow's security model, confirming that this was the source of the vulnerability. The fix was to remove the endpoint entirely.