The Digital Millennium Copyright Act’s so-called “safe harbor” defense to infringement is under fire from a paparazzi photo agency. A new court ruling says the defense may not always be available to websites that host content submitted by third parties.

The safe harbor provision is what has given rise to sites like YouTube and various social media platforms. In essence, safe harbor was baked into the DMCA to allow websites to be free from legal liability for infringing content posted by their users—so long as the website timely removes that content at the request of the rights holder.

But a San Francisco-based federal appeals court is ruling that, if a website uses moderators to review content posted by third parties, the safe harbor privilege may not apply. That’s according to a Friday decision in a dispute brought by Mavrix Photographs against LiveJournal, which hosts the popular celebrity fan forum “Oh No they Didn’t.” The site hosted Mavrix-owned photos of Beyonce Knowles, Katy Perry, and other stars without authorization.