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Researchers Find 6,800 Publicly Discoverable Meta Muse Shares
Security firm Claroc found more than 6,800 Meta Muse share links in passive DNS records, where conversation titles made them searchable. A sample of the pages included personal records and internal business documents, though the researchers
AI.info Team · Written with AI · fact-checked ·
6,800 Muse shares from one search
Meta Muse’s conversation-sharing links turned up in a searchable public record after recipients opened them, according to a security investigation published by Claroc on October 18. The researchers found more than 6,800 hostnames for shared conversations by searching a commercial passive-DNS service, which records domain lookups. The share pages opened without an account or sign-in screen.
Claroc called the pages “GhostShares”: conversations that users had chosen to share with someone, but that other people could find without being sent the link. “If you had asked us beforehand, we would have guessed that gathering these would take real effort. It took one query,” the Claroc Research Team wrote in its report. Claroc Research Team
Conversation titles travel into DNS
Muse creates a web address for each share using the conversation’s title and a random identifier, Claroc found. The hostnames use the domain cf.metaaiusercontent.com. When a recipient opens a link, the browser looks up that hostname; a passive-DNS provider that observes the lookup can record it in a database.
The random identifier may make a link hard to guess, but the DNS record contains the full hostname, including that identifier and the title. That made the links discoverable through a domain search, rather than by guessing addresses or bypassing a login. Claroc also found more than 75 saved Muse-share scans on the public URL-scanning service urlscan.io.
Some pages held personal and company records
Claroc opened a few hundred pages. Most were unremarkable, the researchers said, but a minority contained sensitive material: a small-business loan application, a company revenue review marked for its CEO, and a candidate’s notes for a confidential call with a frontier AI lab. Other examples included a bank-fraud alert with a partial account number and transaction details, a real-estate report with property and mortgage figures, and a workplace vacation calendar listing employees’ time away.
The researchers withheld names, links and identifying details from their report. They said they did not contact the people or companies whose material appeared in the pages, so they could not say what those users intended when they shared the conversations. Claroc reported the issue to Meta’s bug-bounty program on October 8 and said it had no evidence that anyone had misused the shares.
The sample does not measure total exposure
Claroc’s findings describe one search method, one hostname pattern and a short observation window—not every Muse share or how long any page remained accessible. The company’s researchers said they opened only a few hundred of the more than 6,800 hostnames they found. Their content checks took place on October 7 and 8; they re-opened one page on October 18 to capture a redacted screenshot.
Claroc also observed 27 new share hostnames on the last day it checked. The researchers cautioned that this showed continued creation of hostnames, not that each new page had been re-opened and confirmed accessible. They found no evidence of misuse, and their report does not establish that anyone outside the research team viewed the sampled pages.
Meta had not answered the researchers
Asaf Aprozper, Claroc’s co-founder and chief technology officer, told Ars Technica that the firm had contacted Meta and received no reply. He said the company concluded that the sharing behavior was intentional after reviewing similar platforms and Meta’s Muse documentation. “However, users should be aware that when requesting Muse to share a chat with someone, it creates a public link that can be discovered using the passive-DNS techniques we described.” Asaf Aprozper, co-founder and CTO, Claroc
Ars Technica reported that a Meta representative did not immediately answer its questions. Claroc’s report says Muse share pages are accessible to anyone with the link and that the conversation title appears in the hostname. For users and organizations, that means a shared conversation can reveal more than its contents to the person who receives it: the title itself can be recorded and searched through DNS.