External Control of File Name or Path

Summary

eosphoros-ai/db-gpt version 0.6.0 contains a vulnerability in the RAG-knowledge endpoint that allows for arbitrary file write. The issue arises from the ability to pass an absolute path to a call to `os.path.join`, enabling an attacker to write files to arbitrary locations on the target server. This vulnerability can be exploited by setting the `doc_file.filename` to an absolute path, which can lead to overwriting system files or creating new SSH-key entries.