Attackers can exploit the vulnerability to read and delete files and folders from an arbitrary, writable directory as anyone can set the output folder when submitting the request via the outputFolder option.
Openapi generator is a java tool which allows generation of API client libraries (SDK generation), server stubs, documentation and configuration automatically given an OpenAPI Spec. openapi-generator-online creates insecure temporary folders with File.createTempFile during the code generation process. The insecure temporary folders store the auto-generated files which can be read and appended to by any users on the system. The issue has been patched with Files.createTempFile and released in the v5.1.0 …