SSRF in infiniflow/ragflow

A Server-Side Request Forgery (SSRF) vulnerability exists in infiniflow/ragflow version 0.12.0. The vulnerability is present in the `POST /v1/llm/add_llm` and `POST /v1/conversation/tts` endpoints. Attackers can specify an arbitrary URL as the `api_base` when adding an `OPENAITTS` model, and subsequently access the `tts` REST API endpoint to read contents from the specified URL. This can lead to unauthorized access to internal web resources.