Tiger Woods, Katharine McPhee Declare Legal War Over Nude Photo Hacks

Tiger Woods and Katharine McPhee have been hacked -- private nude photos have surfaced -- and their lawyers are vowing to destroy anyone who posts them.

A website has posted graphic selfies of various naked stars, including Tiger, Lindsey Vonn, Miley Cyrus, Kristen Stewart and Stella Maxwell.

We've learned Woods has already unleashed attorney Michael Holtz, who's threatening to sue the site if it doesn't remove the Woods photo STAT.

Sources tell TMZ ... it wasn't Tiger's phone that was hacked, it was Vonn's. We're told Tiger had sent Vonn the naked pic while they were dating.

McPhee has also lawyered up and fired off a similar threatening letter. We're guessing the rest of the stars will follow suit.