Almeida Law Group is investigating a data breach at Cornerstone Staffing Services, Inc. If you were affected, contact Almeida Law Group.
About Cornerstone Staffing Services, Inc.
Cornerstone Staffing Solutions, Inc. is a nationwide recruitment and staffing agency founded in 2003 and headquartered in Pleasanton, California. The company connects businesses with workers across a range of industries and operates approximately 17 to 27 locations throughout the United States, offering temporary, direct-hire, executive search, and onsite staffing services. Because staffing agencies collect detailed personal and financial information from job applicants and placed workers as part of their normal operations, a breach at this type of organization can expose highly sensitive data to serious risk.
What Happened?
On September 12th, 2026, the Vermont Attorney General’s office listed Cornerstone Staffing Services, Inc. in a breach report summary confirming that Social Security numbers, financial account codes, and credit and debit account information were compromised. The number of individuals affected was not disclosed in the filing.
The breach appears connected to a ransomware attack that the Qilin group publicly claimed on November 13th, 2025 — approximately ten months before the Vermont AG filing. According to reporting by Cybernews and SC Media in November 2025, Qilin alleged it exfiltrated 300 GB of data, including resumes of 120,000 job seekers, nearly one million files, and approximately 24 million personal records. SC Media reported that independent analysis of sample files allegedly leaked by the group revealed databases containing names, phone numbers, email and street addresses, Social Security numbers, employee ID numbers, and branch locations, as well as internal banking ledgers, banking statements, invoices, and salary details. These volume and data-type figures are attacker-side claims from Qilin’s leak site and have not been confirmed by Cornerstone or any regulator. The Vermont AG filing remains the only company-side confirmed disclosure of compromised data categories. A federal lawsuit, Hiler v. Cornerstone Staffing Solutions, Inc. (Case No. 5:2026cv02478), has been filed in the U.S. District Court for the Northern District of California in connection with this incident.
Key Facts at a Glance
- Company or Organization: Cornerstone Staffing Services, Inc. (also known as Cornerstone Staffing Solutions, Inc.)
- Industry: Staffing and Recruitment / Human Resources / Business Services
- Location: Pleasanton, California (headquarters); nationwide operations
- Incident type: Data breach (ransomware attack claimed by Qilin group)
- Date breach discovered: September 12th, 2026
- Date of consumer notification: September 12th, 2026
- Prior breach: None identified for this organization
- Litigation status: Hiler v. Cornerstone Staffing Solutions, Inc., Case No. 5:2026cv02478, U.S. District Court, Northern District of California
- Source: Vermont Attorney General breach report summary; Board Cybersecurity incident tracker; Cybernews; SC Media; Justia – Hiler v. Cornerstone Staffing Solutions
What Should You Do?
If you believe your information was involved in this breach, consider placing a fraud alert or credit freeze with all three major credit bureaus — Equifax, Experian, and TransUnion — to make it harder for someone to open new accounts in your name. You are entitled to free weekly credit reports at AnnualCreditReport.com, and you should review them carefully for unfamiliar accounts or inquiries. Because Social Security numbers and financial account information were confirmed as compromised, monitor your bank and credit card statements closely for unauthorized transactions and consider enrolling in any identity theft protection service that Cornerstone may offer to affected individuals. If you believe you have already been a victim of identity theft, visit IdentityTheft.gov for step-by-step recovery guidance.
Your Legal Rights
If your personal information was involved in this breach, you may have legal rights depending on the facts of the incident and the law in your state. Almeida Law Group represents consumers in data breach and privacy litigation and can help you evaluate whether you may have a claim. Contact us at (708) 529-5418 or through our contact page for a free case evaluation.
