Must a Masters thesis involve original research? Can it be merely a review of some recent research direction?
I do not know whether you can do a thesis formally without a supervisor. However, even if it were possible (which I doubt), this is a "Really Bad Idea" (TM). There are very few students who have such a powerful grasp of the topic that they might be able to do an MSc level work without a supervisor, and even they may profit from learning from a more experienced person (Feynman comes to mind who had to learn how to write papers to avoid them getting rejected).

A review of work may be sufficient if it creates a synthetic view of the field, but, again, this is something that only your supervisor can help you decide.

Ultimately, I think the department is responsible to find you a supervisor. They accepted you for the programme. If you have acquired the qualifications entitling you to go forward with the thesis, they have to solve this problem. That being said, the question is why you cannot find a supervisor. Do you have the wrong interests for that department? Or is your profile not strong? If the latter, supervisors may not be enthusiastic to take you on, but then this would not be good starting point to aim for a PhD, though, and definitely discouraged. 

Since you do go for the PhD, I therefore assume you have a strong profile and your department should be able to help you.