Widespread Service Outage at Wisconsin Wireless Provider Cellcom

Wisconsin wireless provider Cellcom has confirmed that a cyberattack is responsible for the widespread service outage and disruptions that began on the evening of May 14, 2025. The incident disrupted voice and SMS services for customers across Wisconsin and Upper Michigan, leaving subscribers unable to make phone calls or send text messages. Cellcom began partial service restoration on May 19, allowing calls and texts between Cellcom users to resume and voice services gradually returning as recovery progressed.

Estimated Cost

Network disrupted >5 days

Threat Source

Impacts

OT IT