It means that a malicious actor would already need to have hacked your computer quite deeply through some other vulnerability (or social engineering) before they could take advantage of this one. But I don’t agree with another commenter here that this is a “nothingburger”: this vulnerability enables such a hacker to leave undetectable malware that you just can’t remove from the computer even if you replace everything but the motherboard. That’s significant, particularly for anyone who might be a target of cyber-espionage.