Design flaw in Meta Muse share links exposes users' private conversations

Meta has paused the sharing feature of its AI agent Muse after the security company Claroc found that the feature's link design made users' private conversations publicly searchable. Muse places conversation titles in subdomains of cf.metaaiusercontent.com; once a link is clicked it enters passive DNS records, and researchers said a single query enumerated 6,800 share links. After opening several hundred of them, they saw information including notes a job seeker prepared for a confidential interview at a frontier AI lab, an internal revenue review at a national marketing company, a small business owner's loan application, a bank fraud alert containing partial account numbers, a real estate investment return table, and an employee's full-year vacation schedule. Claroc co-founder and CTO Asaf Aprozper said the report was submitted on October 8 through Meta's bug bounty program. Meta said it is reviewing the report and considering changing how links can be discovered, and that users no longer face this threat during the pause.