This article describes what you should do if you suspect a data security issue.
If you suspect that you have a data security issue, sent an email to the wrong recipient, shared data with someone by mistake or have been contacted by someone who suspects they have an issue, whether or not they work for the University, please refer to:
https://dataprotection.leeds.ac.uk/reporting-a-data-security-incident/
This page includes information on how to act and who to contact in case of data security incidents.