In CS in the US, you should be fine however you state it. There might be a few exceptions, but as long as the university has a large enough faculty to support both of your interests they will likely be happy to take you other things being equal. The MS level still has a lot of room for "seasoning" and learning what you want to do. There is coursework available in which you can explore each of these more deeply. There is the opportunity to meet faculty who might impress you as being good to work with in one or the other of your interests.
Personally, I see little value in "nailing down" a future too early. There are a lot of variables and there is still time to explore. You don't want to choose arbitrarily and later suffer "buyers remorse".
Note that you will probably be assigned an advisor when you enter. Treat that as a temporary assignment. If you learn you aren't interested in that person's research (or personality) you can (and should) ask another professor to take you on after you learn more about the faculty.
In my own case (long ago) in mathematics I entered interested in both Topology and Analysis. But I don't think the university even knew of that. Once I got there the first courses helped me decide.
There are places, however, and fields, in which you need to be hired into a specific lab in order to be accepted. In such places you need to be "pretty interested" in what that lab does, since you will be participating. It isn't impossible to change in such a situation, but it is harder.
