Cornerstone Staffing Solutions Data Breach Exposes SSNs

Cornerstone Staffing Solutions Inc., a staffing and recruiting firm headquartered in the Dallas/Fort Worth area, disclosed a data breach that occurred in November 2025. So far, 4,425 Texas residents and 243 Massachusetts residents were affected.

Between Nov. 6 and Nov. 21, 2025, an unauthorized actor may have accessed certain systems within Cornerstone's network environment. There were also signs that some data may have been removed from the environment, although the specific files involved could not be determined with certainty.

Dark web monitoring revealed that the ransomware group known as Qilin appeared to claim responsibility for the attack. On Nov. 13, 2025, the group posted on the Tor network, claiming to have obtained data from Cornerstone Staffing Solutions.

The types of personal information that may have been exposed include names, addresses, Social Security numbers, driver's license numbers, government-issued identification numbers (such as passports or state ID cards), financial information (such as account numbers or credit and debit card numbers), medical information, health insurance information and dates of birth.

The breach was additionally disclosed to the California Attorney General. Cornerstone began notifying affected individuals by U.S. mail starting Sept. 11, 2026.

Cornerstone Staffing Solutions' response to the breach

Cornerstone provided guidance on protective measures that affected individuals can take. The company outlined how individuals can place fraud alerts with any one of the three major credit reporting bureaus.

The company also explained how to request a security freeze, which prevents credit bureaus from releasing information from a consumer's credit report without authorization. The notification letters included contact information for Equifax, Experian and TransUnion to assist with these requests.