I’ve no idea how they hacked. But most likely the vulnerability was a mistake the vacuum cleaner manufacturer did, after using second tier software to “save costs”. And they probably skimped on paying the coders, if any

Most likely someone more sophisticated found the exploit, tried to get a bug bounty , was declined by the penny pinching company, and they posted to a place people like your comment inhabit.

If I’m right, this is only the start of problems with this cleaner, because it will happen over and over?