500,000 Volunteers Breached Through Authorised Access: A Controlled Access Buyer's Guide

In April 2026, approved researchers exfiltrated the health records, genetic data, and medical histories of 500,000 UK Biobank volunteers through authorised access channels, then listed the data for sale on Alibaba. The breach was not caused by a hack. It was caused by a model that assumes licence agreements can prevent data theft. This guide covers why that model fails and what physical controls replace it.