Ericsson Inc., the U.S. subsidiary of Swedish networking and telecommunications giant Ericsson, says attackers have stolen data belonging to an undisclosed number of employees and customers after hacking one of its service providers.

Headquartered in Stockholm and founded in 1876, the parent company is a communications tech leader with nearly 90,000 employees worldwide.

In data breach notification letters sent to affected individuals and filed with the California Attorney General on Monday, Ericsson said that a service provider who was storing personal data for employees and customers discovered a breach on April 28, 2025.