WRHN Data Breach Exposes Personal Health Information of 150,000 Patients
The Waterloo Regional Health Network (WRHN) has disclosed a security incident that may have compromised the personal health information of up to 150,000 patients. In a letter dated March 27, 2026, WRHN notified affected individuals that the breach stemmed from a third-party system hosted by Ontario Health used to share patient care details with primary health providers.
The incident, detected and contained on January 13, 2026, occurred outside WRHN’s internal network, which remained secure. WRHN confirmed that clinical records and patient care were unaffected, with the breach resolved within hours of identification. However, the network acknowledged that data from April 2025 to January 2026 including clinical information may have been exposed.
While WRHN’s investigation concluded there was a "low likelihood" of unauthorized access or misuse, the organization is notifying potentially impacted patients as a precaution. No immediate action is required from affected individuals, though WRHN encouraged reporting any suspicious activity. The incident has also been reported to the Ontario Privacy Commissioner. Ontario Health, the third-party provider, did not respond to requests for comment by the deadline.
Waterloo Regional Health Network Foundation (WRHNF) cybersecurity rating report: https://www.rankiteo.com/company/wrhnf
"id": "WRH1775163041",
"linkid": "wrhnf",
"type": "Breach",
"date": "1/2026",
"severity": "85",
"impact": "4",
"explanation": "Attack with significant impact with customers data leaks"{'affected_entities': [{'customers_affected': '150,000',
'industry': 'Healthcare',
'location': 'Ontario, Canada',
'name': 'Waterloo Regional Health Network (WRHN)',
'type': 'Healthcare Network'}],
'customer_advisories': 'No immediate action required from affected '
'individuals; encouraged to report suspicious activity',
'data_breach': {'number_of_records_exposed': '150,000',
'personally_identifiable_information': 'Yes',
'sensitivity_of_data': 'High',
'type_of_data_compromised': 'Personal health information, '
'clinical information'},
'date_detected': '2026-01-13',
'date_publicly_disclosed': '2026-03-27',
'date_resolved': '2026-01-13',
'description': 'The Waterloo Regional Health Network (WRHN) has disclosed a '
'security incident that may have compromised the personal '
'health information of up to 150,000 patients. The breach '
'stemmed from a third-party system hosted by Ontario Health '
'used to share patient care details with primary health '
'providers. Data from April 2025 to January 2026, including '
'clinical information, may have been exposed.',
'impact': {'data_compromised': 'Personal health information and clinical '
'information',
'downtime': 'Resolved within hours',
'operational_impact': 'Clinical records and patient care '
'unaffected',
'systems_affected': 'Third-party system hosted by Ontario Health'},
'investigation_status': 'Concluded',
'references': [{'source': 'WRHN Notification Letter'}],
'regulatory_compliance': {'regulatory_notifications': 'Reported to the '
'Ontario Privacy '
'Commissioner'},
'response': {'communication_strategy': 'Notification letters sent to affected '
'individuals',
'containment_measures': 'Incident contained on January 13, 2026'},
'title': 'WRHN Data Breach Exposes Personal Health Information of 150,000 '
'Patients',
'type': 'Data Breach'}