pyspur Incomplete Filtering of Special Elements allowed by SingleLLMCallNode function

A vulnerability was found in PySpur-Dev pyspur up to 0.1.18. It has been classified as critical. Affected is the function SingleLLMCallNode of the file backend/pyspur/nodes/llm/singlellmcall.py of the component Jinja2 Template Handler. The manipulation of the argument usermessage leads to imprope...