Wi-Fi software security bug could leave Android, Windows, Linux open to attack (Ars Technica)

Not necessarily. For instance, the attacker might succeed in overwriting some data which later isn't used at all, or is used in a harmless way.

Perhaps the code being attacked was something like "if the value at this field is 7, that other field is a function pointer you should use right now, else do nothing; after that, reinitialize all the fields with valid data from elsewhere", and the attacker misaligned the padding and wrote 7 to the wrong field (suppose for the sake of argument that the vulnerability being used doesn't allow for a write outside the object bounds, or a write at any other time than just before that test for 7, and there's no multithreading involved). Unless the attacker hits the correct field with a 7, we have a failed code execution, but which doesn't result in a DoS.