Meta restores Muse sharing after links exposed loan files and revenue data

Meta turned its Muse AI agent's sharing feature back on after fixing a flaw that let outsiders discover links to shared Muse "artifacts," such as documents and images created inside the app. Meta's David Singleton said the underlying issue is now fixed, and that artifacts shared before the fix now have new URLs, with old links showing a message asking visitors to request the new one.

Security firm Claroc had reported that Muse share links lived on a single domain and embedded the conversation's title directly in the web address, which let the links get recorded in passive DNS logs. Using a single query against a commercial passive DNS service, Claroc said it found more than 6,800 Muse share pages, and after opening a few hundred without logging in, found sensitive content including a small-business loan application, a company's internal revenue review for its CEO, a workplace's full-year staff vacation calendar, and a candidate's notes for a confidential call with a frontier AI lab, naming the lab's contact. Claroc said it reported the issue to Meta's bug bounty program on October 8; Ars Technica said Meta paused the sharing feature after it asked Meta about the research.

Meta said the flaw was limited to shared artifacts and did not affect chat sharing. Meta's Muse bug bounty program pays up to $300,000 for valid findings, according to Singleton.

Why it matters

The exposure shows how a simple URL-design choice can turn an AI agent's convenience feature into a way to leak sensitive personal and business data at scale.

Source: The Verge