Data breaches in the week of 28 Sept – 4 Oct 2026

The largest

1. iRhythm Technologies Inc. 8,179,772 patients United States
2. Poppins Payroll Company 246,937 people United States
3. Denver Health Medical Plan 238,083 patients United States
4. World Acceptance Corporation 232,401 people United States
5. Technical University of Denmark (DTU) 200,000 current and former users Denmark
6. Baltimore Medical System Inc 197,201 people United States

Every breach this week, by country

United States 67

• iRhythm Technologies Inc. 3 October 2026 · 8,179,772 patients
• Cerner Corporation 2 October 2026 · 2,992,244 Texas residents
• DriveWealth 29 September 2026 · 2,556,688 Texas residents
• Poppins Payroll Company 29 September 2026 · 246,937 people
• Denver Health Medical Plan 1 October 2026 · 238,083 patients
• World Acceptance Corporation 30 September 2026 · 232,401 people
• Sheppard, Mullin, Richter & Hampton LLP 2 October 2026 · 204,001 Oregon residents
• Baltimore Medical System Inc 29 September 2026 · 197,201 people
• Atlantic Digestive Specialists, PLLC 30 September 2026 · 173,853 patients
• City of McMinnville 29 September 2026 · 122,864 people
• American Family Connect Insurance Company 30 September 2026 · 52,798 people
• Midvale Indemnity Company 30 September 2026 · 38,381 Oregon residents
• Universal Dermatology & Vein Care 30 September 2026 · 35,295 patients
• Trinity Health 30 September 2026 · 33,234 patients
• PeoplesBank 28 September 2026 · 27,624 people
• Pavillon International Inc 29 September 2026 · 8,813 people
• Bright Smile Dental Care 1 October 2026 · 7,601 patients
• Lamb Weston Holdings, Inc. 29 September 2026 · 7,175 people
• Lincoln Property Company Commercial LLC 1 October 2026 · 6,585 Texas residents
• Bay Area Psychological Consultants 1 October 2026 · 5,679 patients
• Nishiyamato Academy 30 September 2026 · 5,507 people
• McKenzie Creative Brands 30 September 2026 · 4,399 people
• Arkansas Urology, P.A. 1 October 2026 · 4,347 patients
• Borger Independent School District 29 September 2026 · 4,232 Texas residents
• Association of the Bar of the City of New York 29 September 2026 · 3,847 people
• Pro Holdings, LLC d/b/a ProCamps 2 October 2026 · 3,840 Texas residents
• 7 to 7 Dental & Orthodontics 2 October 2026 · 3,526 Texas residents
• Aldrich Services LLP 1 October 2026 · 3,202 Oregon residents
• The Woodlands Arts Council 30 September 2026 · 2,923 people
• Martin Brother Distributing Company, Inc. 29 September 2026 · 2,303 patients
• PSI Premier Specialties Inc. d/b/a Medical Express PSI 2 October 2026 · 2,128 Texas residents
• Indiana University Health, Affiliated Covered Entity 29 September 2026 · 2,080 patients
• MEBS Global Reach 30 September 2026 · 2,068 people
• KLA Laboratories Inc 28 September 2026 · 1,788 people
• Pay Tel Communications Inc 28 September 2026 · 1,717 people
• Innovative Alternatives, Inc 2 October 2026 · 1,500 patients
• Blair C Diaz CPA PC 28 September 2026 · 1,465 people
• PDCM Insurance 29 September 2026 · 1,046 Texas residents
• i.e.Smart Systems, LLC 2 October 2026 · 897 Texas residents
• Wooddesign RV Interiors LLC 28 September 2026 · 763 people
• Ozark Interests, Inc. 29 September 2026 · 564 Texas residents
• ViewSonic Corporation 30 September 2026 · 540 people
• Health Prime International 29 September 2026 · 501 patients
• Deer Management Co. LLC dba Bessemer Venture Partners 30 September 2026 · 431 people
• Goldston Oil Corporation 2 October 2026 · 412 Texas residents
• Integrated Sleep and Weight Specialists 29 September 2026 · 404 Texas residents
• Fragomen, Del Rey, Bernsen & Loewy, LLP 2 October 2026 · 379 Texas residents
• Texas Mutual Insurance Company 29 September 2026 · 265 Texas residents
• American Motorcyclist Association 30 September 2026 · 200 people
• Smith Dollar 28 September 2026 · 109 people
• Chicago Psychoanalytic Institute 29 September 2026 · 57 people
• Reminger Co LPA 28 September 2026 · 22 people
• Petrovits, Patrick, Smith & Company, LLC 29 September 2026 · 4 Vermont residents
• The Hudson River Museum of Westchester, Inc. 4 October 2026 · 2 Vermont residents
• Family Medical Associates of Raleigh, PA 2 October 2026 · 2 Vermont residents
• Heuer Publishing 2 October 2026 · 2 Vermont residents
• Virgo Gems, LLC 1 October 2026 · 2 Vermont residents
• Live Nation Entertainment, Inc. 1 October 2026 · 2 Vermont residents
• DentaQuest 28 September 2026 · 2 Vermont residents
• The Woodlands Art Council 30 September 2026 · 1 Vermont residents
• Indico Data Center 28 September 2026 · 1 Vermont residents
• Marana Health Center 1 October 2026
• Securities Support Unit, LLP 1 October 2026
• ProCamps 30 September 2026
• Challenge Financial Services, Inc. 29 September 2026
• Martin Brothers Distributing Company, Inc 29 September 2026
• San Bernardino County on behalf of Arrowhead Regional Medical Center 28 September 2026

Denmark 1

• Technical University of Denmark (DTU) reported 2 October 2026 · 200,000 current and former users

Ransomware claims

Gangs named 232 organisations on their leak sites this week, against 202 the week before. A claim is the gang’s word, not a confirmed breach.

• The Gentlemen 34 claims
• Qilin 15 claims
• Storm 15 claims
• SafePay 12 claims
• INC Ransom 10 claims
• Akira 9 claims