Meta Muse GhostShares privacy flaw

Meta paused its Muse AI assistant's conversation-sharing feature after security firm Claroc found that more than 6,800 shared chats were discoverable through public passive DNS lookup services without needing the original link. The exposure stems from how Muse constructs share URLs: the conversation title is embedded in a subdomain alongside a short random code. Passive DNS services log address lookups the first time a page is opened and publish the full URL in searchable databases, making the random code itself retrievable. Ars Technica reported Claroc performed the enumeration using a single query. Among the pages accessed were a job candidate's prep notes for a confidential AI lab call, an internal revenue review, a loan application, a bank fraud alert, real-estate data, and a staff vacation calendar. Claroc labeled the exposed pages 'GhostShares,' describing them as 'pages that open for people who were never handed the link, and that those people can find on their own.' Claroc's CTO said the flaw appeared to be intentional design rather than a coding error, and that Meta did not respond to the firm's outreach before publication. Claroc reported the issue via Meta's bug bounty program on October 8, 2026. Meta paused the sharing feature roughly one day after Claroc published its findings, describing the response as suspending the feature while reviewing it and considering changes. The disclosure sits alongside Zuckerberg's description of Muse as 'built from the ground up for privacy and security.'