[dzaima]

If a process uses the execv* methods to spawn a new process (as should most good implementations), it doesn't use /bin/sh in any way and thus itself cannot cause wrong things to happen; the spawned process could of course still do arbitrary computation on its inputs including introducing vulnerabilities, but that'd be strictly not the caller's fault and the caller couldn't do anything about it - there's only one format a given list of arguments can be passed to execv* and the spawned process still gets the arguments separately, whereas on Windows the spawned process can forego the standard unescaping completely.

At the core really is that on Linux the arguments provided as a list of separate arguments is The Format of arguments, so it can be exposed and used without question, whereas on Windows the native format is a single string which can still be used to achieve the same things, but now the callee must necessarily know what way the caller expects multiple arguments (if it does at all) and stdlibs so far had just been assuming one format where bat files have a different one.