Hackers have placed data that was captured on the dark web three weeks ago during a hack at educational institution ROC Mondriaan in The Hague.
The data contains sensitive information, such as complaints handling and personal data of teachers and students.
The data, viewed by NU.nl, was shared on a hacker site on the dark web, the protected part of the internet.
Why the data was published, and whether it was stolen in a ransomware attack, is unclear.
In such an attack, data is encrypted until the victim pays money.
A spokesperson for ROC Mondriaan informs NU.nl that he cannot say whether the school has been approached by hackers and whether the school has paid any ransom.
The data shared by the hackers contains a lot of sensitive information, such as class lists, emails to parents and personal data of students and teachers.
Furthermore, the school's financial records and business protocols have been leaked.
It is not clear why the data was made public.
The educational institution says in a response that it cannot say more yet.