A nationwide data breach against a cloud-based software provider has hit at least four school districts on Long Island, potentially exposing sensitive information, officials said.

According to district officials, the Massapequa, Smithtown Central and Uniondale school districts, as well as Nassau BOCES, were affected by the breach by California-based PowerSchool.

PowerSchool is a cloud-based software company that provides student information services to more than 16,000 customers and more than 50 million students worldwide, according to its website. On Dec. 28, the company notified customers of a “cybersecurity incident,” Matthew C. Ritter, assistant superintendent for data, planning, evaluation and accountability for the Uniondale School District, said in a statement Friday.

“Unauthorized access was gained to certain systems, potentially exposing the personal information of employees with PowerSchool accounts,” Ritter said. “Compromised data may have included employee names, phone numbers, addresses and social security numbers.”

PowerSchool said in a statement to Newsday on Sunday: “PowerSchool is not experiencing or expecting any interruption in operations and is continuing to provide services to our customers as usual.” We have no evidence that other PowerSchool products were affected as a result of this incident.”

The hacker gained access to the PowerSchools Student Information System, also known as SIS, using a “compromised credential,” the company previously wrote in a letter to affected school districts across the country.

“We can confirm that the information accessed belongs to specific (Student Information System) customers and relates to families and educators, including those at your organization,” the letter said. “The unauthorized access point has been isolated to our PowerSource portal. Because the PowerSource portal only allows access to the SIS database, we can confirm that no other PowerSchool products were affected by this incident.”

Larry Leaven and James Widmer, district superintendent and assistant superintendent of Nassau BOCES, respectively, said in a joint statement that PowerSchool informed the district that “the security breach has been fully remedied.”

“Our team is working closely with PowerSchool to fully understand the scope of the breach and ensure our data remains secure,” the statement said. “We will continue to monitor the situation and provide updates as necessary.”

A Massapequa district representative said in a statement that PowerSchool said the breach affected a “significant number of schools.” A Smithtown Central district representative said in a statement that PowerSchool is “working with the FBI and cybersecurity experts.”

“Out of an abundance of caution, password resets are being initiated as a precautionary measure,” Massapequa’s statement continued.

PowerSchool said in its letter that it “did not expect the data to be shared or published, and we believe it was deleted without further reproduction or distribution.”

Joshua Needelman covers the town of North Hempstead for Newsday. He is a Long Island native and graduate of the University of Maryland. His work has appeared in publications such as The New York Times and The Washington Post.