Hackers raise temperatures at French blood storage sites

Unknown attackers breached refrigeration controls at French blood-storage facilities overnight on 2 November 2026 and raised temperature settings to as high as 110 degrees Celsius. The French Blood Establishment (EFS) said the intrusion affected cold stores operated by a contractor. Technicians noticed the rising temperatures and moved products before any were compromised.

Plasma intended for transfusion and samples kept for safety monitoring were among the materials stored in the affected rooms. Normal storage temperatures for frozen plasma are minus 30 degrees Celsius or lower. The EFS later confirmed to Le Canard enchaîné that transfusion plasma had been involved. It stated that no blood products or samples were ultimately altered because alarms and on-site response allowed rapid intervention.

The EFS is France's public blood operator. It collects, tests and distributes blood, plasma and platelets to more than 1,900 hospitals and supports more than a million patients each year. The agency has reinforced monitoring of all its equipment and has alerted the national cybersecurity agency ANSSI and the health ministry.

The incident forms part of a wider pattern of attacks on refrigeration systems across Europe in the same period. Supermarket freezers in Italy, Germany, Romania, the United Kingdom, Belgium, Estonia, Ireland, Finland, Luxembourg, the Netherlands and Sweden reported sudden temperature spikes reaching 50 degrees Celsius, causing food losses valued in the millions of euros. Investigators have not publicly identified the actors or confirmed whether the blood-facility and supermarket attacks are linked.

In the French case the attackers appear to have reached the controls through a third-party contractor, Coolworld, that manages the refrigeration systems. The EFS said it was not directly targeted. Products were relocated to other sites. The episode has highlighted the exposure of critical health infrastructure that relies on external operators for environmental controls.

European authorities have increased scrutiny of industrial control systems after the series of incidents. Blood-product storage is temperature-critical; even a short period above the required range can render plasma unusable for transfusion. The successful intervention in France prevented that outcome, but the breach demonstrated that the systems can be reached remotely.

No group has claimed responsibility. French officials have not released further technical details of the intrusion. The combination of the blood-service incident and the simultaneous supermarket attacks has prompted calls for tighter segmentation of contractor access and for mandatory offline alarms on medical cold-chain equipment.

The EFS continues to operate normally. Hospitals have not reported shortages linked to the event. The longer-term consequence is the reminder that the cold chain for blood products depends on digital controls that can be altered from outside the facility if contractor systems are compromised.