Grok Build, the app-building agent from SpaceXSI, exposed stored data from thousands of user projects through shareable grok.me links that could be listed in public DNS records, according to research reported Tuesday by Ars Technica¹.

Security firm Claroc told Ars that a passive DNS search returned 43,601 hostnames ending in grok.me, and that more than 35,000 of those links, nearly 95 percent, opened the corresponding app and the data it stored¹. Claroc co-founder and CTO Asaf Aprozper said tests over the past week showed Grok Build set new shares to anyone with the link unless the user changed the setting to invited users or only you¹.

Ars said Grok Build share URLs put randomly generated phrases, sometimes called dice words, to the left of the grok.me domain, and that users can change those phrases¹. Claroc said that placement lets passive DNS services capture previously unseen hostnames when they are looked up, unlike share schemes that put the secret in the URL path, where DNS does not see it¹.

Claroc said it found 24 apps built by SpaceXSI itself, the name Ars used for the merged SpaceX and xAI, and that those apps showed internal material including a confidential onboarding plan for an enterprise sales hire, a sales territory map of 594 accounts, internal addresses for sales tools, and advertising proposals¹. Ars said those 24 apps were still exposing data Monday evening and that SpaceXSI began removing the links within hours of Ars sending questions; by publication the 24 links returned an app-not-found error¹.

Other examples Claroc described to Ars included an occupational-health dashboard with 3,784 worker medical exams at a Peruvian construction company, a Tesla service-center scorecard naming 22 technicians, a roster of 108 people on a U.S. Navy logistics support contract, a luxury-cruise galley checklist with crew names and employee IDs, a hospital staff roster of about 3,565 employees, and other business files from construction, transport, hosting, and defense-related users¹. Aprozper said he was notifying companies; after he spoke with the luxury cruise company's CISO, Ars reported that firm pulled in its security team and began containing the exposure¹.

A representative with Cursor, the AI coding service Ars said SpaceXSI recently acquired, told Ars by email that Grok Build apps are private by default and that nothing goes public unless the creator chooses to share it, and that competing coding agents also offer shareable links¹. Ars said Aprozper's tests contradicted the private-by-default claim and that, in the cases he checked, users had to change the anyone-with-the-link setting themselves¹. The representative did not answer follow-up questions Ars said it sent about whether SpaceXSI meant to expose its own internal apps, why the company removed them after questions, or whether it planned to notify other customers¹.

Aprozper told Ars that Lovable, Bolt, and Replit also give apps web addresses that can show up in DNS, but that Grok was where Claroc found the most sensitive company data¹. Ars noted that Claude published artifacts, ChatGPT shared conversations, and Gemini shares put randomness in the path instead¹. Ars also cited Meta's Muse agent recently suspending a link-sharing feature after a similar exposure report¹.