Redash: DuckDB query runner allows arbitrary file read/write via unrestricted external access

Redash is a package for data visualization and sharing. From 26.0.0 until 26.9.0, the DuckDB query runner's _connect() path in redash/query_runner/duckdb.py created connections with enable_external_access left at its default value of true. A user with query access to an administrator-created DuckDB data source could use native file-reading functions to retrieve files readable by the Redash process or use COPY TO to write files with that process's privileges. Reading application secrets such as REDASH_COOKIE_SECRET or REDASH_SECRET_KEY could also enable forged sessions and authentication bypass. This issue is fixed in version 26.9.0.