Cyberattack Targets French Blood Storage Freezers, Hackers Attempt to Raise Temperatures to 110°C
A cyberattack targeting a contractor responsible for maintaining refrigeration equipment used by France’s national blood service has compromised blood-storage freezers, with hackers attempting to change their temperature settings from approximately -30°C to 110°C.
The incident took place overnight between November 1 and 2, 2026, and was first reported by French investigative weekly Le Canard enchaîné.
The targeted company, Coolworld, provides maintenance services for temperature-controlled storage containers and refrigeration equipment used by the Établissement Français du Sang (EFS), France’s national blood service. Facilities in the Bourgogne-Franche-Comté region were among those affected.
The freezers are normally maintained at around -30°C to preserve blood samples and other temperature-sensitive medical products. However, attackers allegedly manipulated the control systems, instructing the equipment to reach temperatures of up to 110°C.
The attempted manipulation was detected by an on-call technician who noticed rising temperatures during the night and immediately alerted the relevant teams. This enabled authorities and technical staff to respond quickly and prevent any reported disruption.
France’s Health Ministry said there were “zero operational consequences”, adding that the incident had no impact on the transfusion chain or patient safety.
Initially, the EFS described the affected contents as donor samples retained for transfusion-related health monitoring. However, it later confirmed to Le Canard enchaîné that frozen plasma intended for patient transfusions was also stored in the affected freezers.
Fresh frozen plasma must be maintained at temperatures of -25°C or below, as prolonged exposure to higher temperatures can compromise its usability. Nevertheless, authorities have not confirmed that any plasma was destroyed, that transfusions were delayed or that the stored products actually reached the extreme temperatures programmed by the attackers.
Officials have also clarified that the 110°C figure represented the temperature setting entered into the freezer controllers, not a verified temperature inside the storage units or the plasma products themselves. The actual temperatures reached and the duration of any temperature increase have not been publicly disclosed.
The incident comes amid a growing pattern of cyberattacks targeting refrigeration systems across Europe.
In October 2026, hackers reportedly compromised refrigeration controllers in hundreds of French supermarkets, forcing equipment into prolonged defrost mode and causing temperatures to rise as high as 50°C. The attacks resulted in extensive food spoilage. A further wave reportedly affected stores in several other European countries in early November.
Earlier, in August 2026, researchers from Claroty’s Team82, an industrial cybersecurity research group, disclosed serious vulnerabilities in widely used commercial refrigeration controllers manufactured by Danfoss and Copeland/Dixell.
The vulnerabilities included authentication bypasses and remote code execution risks, potentially allowing attackers to manipulate temperature settings and cooling functions.
Claroty demonstrated in controlled laboratory tests that compromised systems could be instructed to display or target extreme temperatures, including levels exceeding 100°C, while potentially concealing the actual operating conditions.
The company reported the vulnerabilities to the manufacturers, which subsequently issued security patches. Claroty researchers did not conduct attacks against real-world refrigeration facilities but highlighted weaknesses that could expose internet-connected systems to cyber threats.
Investigations into the French blood-storage incident are continuing. Authorities have yet to identify those responsible, establish how the attackers gained access or confirm which specific refrigeration controllers were compromised.
The incident has raised fresh concerns about the cybersecurity of critical medical infrastructure and the risks associated with third-party contractors managing sensitive healthcare and food-supply systems. Officials maintain that the rapid detection and response prevented any consequences for patients or France’s blood supply.
