Meta suspends Muse chat sharing after 6,800 links leak via DNS

Meta has suspended Muse's conversation-sharing feature after security firm Claroc surfaced more than 6,800 shared chat links through a single public-DNS search, Ars Technica reported. The share URLs sit under the domain cf.metaaiusercontent.com, and because Muse builds each one from the conversation's own title plus a random string, titles like 'loan-application-draft' and 'q3-revenue-review' ended up written into DNS where anyone running a passive lookup could enumerate them.

"Muse names each share's web address after the conversation's own title, and that address is written into public DNS," Claroc said in its blog post. "One passive-DNS search brings back thousands of them, listed by name, like a table of contents."

Most of the pages Claroc opened were harmless: small-business sites, listings and event calendars. But a minority carried material users plainly did not expect to be reachable without the link. Among them were a candidate's prep notes for a confidential call with a frontier AI lab about an executive search, which named the lab's internal contact and the time of the meeting, an internal revenue review addressed to the CEO of a national marketing company, a loan application from a small-business owner, and a to-do list containing a bank fraud alert that displayed part of an account number.

Claroc, which named the findable pages 'GhostShares,' reported the flaw to Meta's bug bounty program on Oct. 8. Meta told Ars Technica it was suspending the feature after the outlet asked about the findings; Claroc said it was "glad to see it closed this quickly" and that it had no evidence anyone had misused the shares.