Parents and educators are receiving notifications about the breach, but it’s still unclear exactly how many people have been affected or what information was leaked.

PowerSchool Holdings Inc. is facing three federal lawsuits alleging the education software provider negligently failed to protect the personal information of students, parents, and teachers that was exposed in a December data breach.

The breach is the latest in a series of high-profile cybersecurity incidents affecting K-12 schools, which are a top target of hackers and are uniquely vulnerable to cyberattacks.