FlatPress is a blogging engine that saves your posts as simple text files. Forget about SQL! You just need some PHP.
The vulnerability is caused due to the improper verification of uploaded files via the Uploader script using 'upload[]' POST parameter which allows of arbitrary files being uploaded in '/fp-content/attachs' directory. The application interface allows users to perform certain actions via HTTP requests without performing any validity checks to verify the requests. This can be exploited to perform actions with administrative privileges if a logged-in user visits a malicious web site resulting in execution of arbitrary PHP code by uploading a malicious PHP script file and execute system commands.