GHSA-jwm3-qcfw-c5pp: n8n: Python Code Node AST Validator Bypass

An authenticated user with permission to create or modify workflows containing a Python Code node could bypass the AST security validator and access the task executor module namespace. On self-hosted instances where N8N_BLOCK_RUNNER_ENV_ACCESS=false is set, this extended to disclosure of environment variables accessible to the task runner process.

This issue only affects instances where the Python Task Runner is enabled and N8N_BLOCK_RUNNER_ENV_ACCESS=true.