Data breach puts medical info of 462,000 Blue Cross Blue Shield Montana customers at risk

The private medical information of more than 462,000 Montanans may have been exposed in a data breach involving a third-party vendor used by Blue Cross Blue Shield of Montana, according to a report submitted to the state auditor’s office.

Documents obtained by Lee Newspapers through a records request show that Social Security numbers, birth dates and medical service details - including treatment and diagnosis codes, provider names and claim amounts - for current and former customers of Blue Cross Blue Shield Montana, the state’s largest health insurer, may have been compromised in the leak.

The breach lasted from October 2024 to January 2025, according to a report submitted by a lawyer representing the insurance company, but was not reported to state regulators until earlier this month,