You have the right to information about data breach
Data leakage, data loss or data disclosure to unauthorised persons – it happens. And this poses a serious threat to you, so do not be surprised that the controller informs you about it - this is the controller’s obligation. Follow its instructions to minimise the threat. Sometimes, e.g. changing the password in the Internet system or putting a hold on the documents will allow you to protect your data and avoid, e.g. the identity theft and the related consequences, such as e.g. incurring loans on your behalf.
If you have doubts contact the controller or the data protection officer appointed by the controller to assist you in this situation.