If you know how to code and you audit the code and compile it yourself from the source code ? Then it is 100% safe.
If the program is from a well regarded community and the source code is easily accessible to the public and it has been regularly reviewed by experts ? Then it is pretty safe.
If the program is from an unknown source and the source code is difficult to access by the public or it is obfuscated and no reviews are available? It is probably better to give it a miss and keep looking for a program that is more trustworthy which suits your needs.