Hackers gained access to data held by the University of Copenhagen covering roughly 525,000 people. The university confirmed the intrusion and gave the scale of the breach in its own statement. What kind of information was touched, whether it concerns students, staff or others, has not been laid out in detail. A breach of this size ranks among the more serious ones reported by Danish institutions in recent memory. Universities hold large stores of personal data, from admission records to payroll files, which makes them attractive targets for attackers. Work is now under way inside the university to trace how the intruders got in and what exactly they reached. People whose details could be involved are the ones most directly affected. The case is likely to feed a wider discussion about data security at European universities.