Got stuck with overambitious master thesis
Your situation is quite common with MS theses (in the US at least). There are several people who are given ideas from their advisors which either turn out to be dead-ends or take up much more than the allotted time. In EECS, the MS thesis defense is more about displaying your ability to conduct research than having significant results. Clearly describe the problem, your methods, and display preliminary results whether they are significant or not.

As an example, a professor in my university is interested in inverse problems in imaging. Every once in a while he takes up a student for an MS thesis for denoising images. Problem is, nothing really beats an algorithm called BM3D in terms of PSNR for denoising images (except in specific circumstances). So he has had a few MS students who developed a new method which didn't work as well as BM3D but nonetheless conducted meaningful research and successfully defended. Everyone on your committee knows that it is impossible to anticipate whether an idea will actually work before doing it.

Switching topics and advisor halfway through might not work (how do you know that a new idea is doable in time before actually doing it?). Usually, this is best reserved for situations where there are inter-personal conflicts. Assuming that your advisor is looking out for your best interests, schedule a meeting and talk to them about your concerns with the amount of time you have left and what aspect of the project you should focus on.