Builders FirstSource Data Breach Exposes Personal and Health Information for Individuals

Builders FirstSource Flex Plan, an entity connected to the building materials company Builders FirstSource Inc., disclosed a data breach that affected 1,514 individuals in the United States, including residents of Massachusetts.

The breach was reported to the U.S. Department of Health and Human Services on Feb. 18, 2026, as well as to the Massachusetts Attorney General, though details about the nature and purpose of this plan are not publicly available at this time.

Before the breach was officially reported to federal regulators, a threat actor known as Leaknet posted a claim on the dark web on Dec. 30, 2025. Leaknet alleged that it had obtained data from Builders FirstSource and stated it intended to publish the stolen information within one day.

Because the incident was disclosed to the HHS, it involved protected health information. However, the specific types of health information that were exposed in this breach have not been itemized in publicly available disclosures. The incident has exposed names, financial account information and Social Security numbers.

Builders FirstSource Flex Plan's response to the breach

Affected individuals should watch for direct communication from Builders FirstSource Flex Plan in the mail. Breach notification letters provide specific details about what data was involved, what the organization is doing in response, and what resources are being offered to help protect those who were affected.

Anyone who believes they may have been affected by this breach and has not yet received a notification letter may want to contact Builders FirstSource directly for more information.