Meta's Muse AI agent found to expose private data through predictable share links

Researchers from security firm Claroc reported Monday that they were able to enumerate 6,800 links Muse users had created to share conversations with other people. After opening a few hundred of them, the researchers found material that was clearly not intended to be publicly available, including personal and business secrets.

The issue stems from a central design decision in how Muse constructs its share URLs. Like many online services, Muse lets users share searches, conversations, images and similar content through a unique link. Such links usually contain a long, hard-to-guess sequence of text, and Muse appears to follow the same precaution. But Claroc said the way Muse builds these URLs makes them easy to discover.

Meta CEO Mark Zuckerberg said last month that Muse was "built from the ground up for privacy and security." The researchers' findings put that claim under direct scrutiny, though the published report does not include a response from Meta.

Analysis

Why This Matters

Anyone who shared a Muse conversation may have exposed personal or business information to people it was never meant for.
Because the links could be enumerated, the exposure is not limited to individual cases: a large set of conversations was discoverable by automated scanning.
The finding directly tests Meta's public positioning of Muse as a privacy-first and security-focused product.

Background

Many online services rely on "unguessable" URLs to protect shared content. The security model assumes that a link containing a long random string cannot be found by people who were not given it. Researchers say Muse's URL construction undermined that assumption, allowing them to walk through a large number of links and open contributed conversations.

Key Perspectives

Claroc researchers: The design of Muse's share links makes conversations discoverable, and live examples contained information clearly never intended for public view.

Meta: The company has publicly described Muse as built for privacy and security. The report recorded no response from the company to the researchers' findings.

Critics and skeptics: The practical harm depends on how many of the enumerated links were opened before the issue was identified, and whether the exposed information has spread beyond the researchers' review.

What to Watch

Whether Meta changes Muse's share-link construction or releases a fix.
Whether the 6,800 enumerated links are closed or remain accessible.
Whether the exposure draws regulatory attention or further disclosure demands from affected users.

Checked

9 claims in this story checked against 1 source: 5 supported.

Show each claim

Partly supportedMuse exposes private data through predictable share links.Ars Technica - All content: “But a central design decision for constructing URLs has made the links easy to discover.”
Partly supportedResearchers enumerated 6,800 shared conversations.Ars Technica - All content: “researchers from security firm Claroc said they were able to enumerate 6,800 links Muse users created for sharing conversations with others.”
SupportedResearchers found information that was never meant to be public, including personal and business secrets.Ars Technica - All content: “After opening a few hundred of them, the researchers found information that was clearly not intended to be publicly available, including:”
SupportedMuse is Meta’s new general-purpose AI agent and can expose sensitive information when users share conversations through web links.Ars Technica - All content: “Muse, the new general-purpose AI agent from Meta, can expose sensitive information when users share conversations through Web links, researchers reported Monday.”
SupportedClaroc researchers reported Monday that they could enumerate 6,800 links.Ars Technica - All content: “researchers from security firm Claroc said they were able to enumerate 6,800 links Muse users created for sharing conversations with others.”
SupportedMuse’s URL design was apparently intended to keep shared content private.Ars Technica - All content: “To keep potentially sensitive information from being accessible to unintended people, the URLs typically contain a long sequence of text that can’t be easily guessed. A single query is all that's required Muse, which Meta CEO Mark Zuckerberg said last month was “built from the ground up for privacy and security,” seems to take the same precautions.”
SupportedZuckerberg said Muse was “built from the ground up for privacy and security.”Ars Technica - All content: “Meta CEO Mark Zuckerberg said last month was “built from the ground up for privacy and security,””
Not in the sourcesThe findings put Zuckerberg’s privacy-and-security claim under direct scrutiny.Ars Technica - All content
Not in the sourcesThe published report does not include a response from Meta.Ars Technica - All content