The Maine Office of the Attorney General reported a data breach involving UScellular on February 13, 2024. The breach occurred on January 28, 2024, due to an external system breach (hacking), affecting 100 individuals, including 8 residents. Information compromised includes customer account numbers, names, addresses, and PIN codes, but sensitive personal information such as Social Security numbers and credit card details is masked and was not accessed.

The Federal Communications Commission (FCC) disclosed a data breach affecting UScellular in early November 2022. Between October 29 and October 31, 2022, unauthorized actors gained access to the company’s systems, compromising customer billing information, including names, addresses, PIN codes, and cellular telephone numbers. While the exact number of impacted individuals remains undisclosed, the breach exposed sensitive personal data that could facilitate identity theft, SIM-swapping attacks, or targeted phishing campaigns. The incident highlights vulnerabilities in UScellular’s security protocols, raising concerns over the protection of customer data. Although no financial records (e.g., credit card details) or highly sensitive information (e.g., Social Security numbers) were reported as stolen, the exposure of PIN codes—often used for account authentication—poses a significant risk of fraudulent account takeovers. The breach underscores the growing threat of cyber intrusions targeting telecom providers, where even non-financial data can be weaponized for malicious purposes. UScellular has not publicly detailed the attack vector, but the FCC’s involvement suggests regulatory scrutiny over compliance with data protection standards.

US mobile carrier in UScellular was hacked in December 2021 and its data was compromised in the attack. The personal information of 405 clients was stolen and the attackers also ported some of the affected customers' numbers. The company immediately disconnected the computer accessed by unauthorized individuals from the internet to contain the attack.

The Maine Office of the Attorney General reported a data breach at US Cellular on September 18, 2020, involving hacking. The breach affected a total of 78 individuals, with 1 resident specifically impacted. The breach was discovered on September 23, 2020, and notifications were sent out on October 3, 2020.