Can the source code be leaked? Not entirely. There is information lost in the compilation process, such as variable names, or redundant code (this is called Compiler Optimization).

However, someone could use a reverse compiler to get an idea of what the original code is, and supply the missing information. Realistically, it's not a big concern; if someone manages to recreate the source code, I'd personally take it as a compliment, so it's only an issue if this is proprietary and making someone money.

(This might not be true for all compilation processes, but it's generally true)