Hackers Hit French Blood Service Freezers, Setting Them to 110C

By Economy Media Newsroom · November 4, 2026

Hackers took remote control of refrigeration systems at France’s national blood service overnight from Nov. 1 to Nov. 2 and changed the settings on cold rooms that hold donor blood samples and frozen plasma, French officials and the service said. Rooms normally kept at about minus 30 degrees Celsius (minus 22 Fahrenheit) were reprogrammed to a target of 110 degrees Celsius (230 Fahrenheit). The attack is the latest and most alarming in a run of cyberattacks on cold storage across Europe that has already hit hundreds of supermarkets.

An on-call technician noticed the unusual rise in temperature during the night, allowing staff to step in before blood products were harmed, according to the service. France’s Health Ministry said the incident had no operational consequences for transfusions or for patients.

What happened

The target was the Établissement français du sang (EFS), the state-run agency that collects, tests and supplies all donated blood in France. The affected cold rooms were in the Burgundy and Franche-Comté region of east-central France, Infosecurity Magazine reported. The Guardian reported that the EFS said temperature and defrosting thresholds had been raised to “very high levels” at three cold stores.

The incident was first made public on Nov. 3 by Le Canard enchaîné, a French investigative weekly. According to the newspaper, the attackers did not break into the EFS itself. Instead, they reached the systems through Coolworld, a Dutch company that rents out temperature-control equipment and maintains the blood service’s refrigeration controls. Coolworld operates in France, Germany, Ireland, the Netherlands and the United Kingdom.

In a statement dated Nov. 4, Coolworld said it was aware of a cybersecurity incident “involving remote monitoring software used in refrigeration systems” and had “responded promptly by implementing the appropriate measures,” without saying what those were, Infosecurity Magazine reported. The company said only a limited number of its units were affected and that the weakness lay in a component supplied by a third-party provider rather than in its own products.

Frédéric Pacoud, president of the EFS, told the French broadcaster BFMTV that the service “could have lost samples or bags of plasma intended to treat patients,” but that the early warning meant there had been no compromise to the safety of blood products, according to Infosecurity Magazine.

What is still unknown

Officials stressed that the 110-degree figure was a setting, not a measured temperature. The Health Ministry said it was the programmed target value and not the temperature actually reached, the Swiss outlet blue News reported, citing Le Canard enchaîné.

Several key questions remain open:

• How many cold rooms were affected, and how high temperatures actually rose before staff intervened.
• How long the altered settings stayed in place.
• Who carried out the attack and how the attackers got access.

There is no indication so far that donor data was stolen, blue News reported, and Infosecurity Magazine said nothing suggests the EFS’s own IT systems were breached. Investigators have not formally linked the blood service attack to the earlier supermarket incidents, according to the French daily 20 Minutes, as cited by blue News.

A wider wave of attacks

The blood service breach came on the same night that supermarkets in several other countries reported overheating fridges and freezers. Stores belonging to Ahold Delhaize, the Dutch-Belgian grocery group, in Belgium and Luxembourg were affected, as were the Swedish chains ICA and Coop, blue News reported. By Tuesday, the list had grown to about a dozen countries, including Germany, Romania and the United Kingdom, and Belgium’s federal prosecutor’s office had opened an investigation.

The pattern echoes a mid-October attack in France. On Oct. 13, Al Jazeera reported that hackers had remotely forced cooling systems at hundreds of French supermarkets into defrost mode, heating fridges and freezers to as much as 50 degrees Celsius (122 Fahrenheit), spoiling food and causing fires at several stores. Retailers told the news agency AFP that at least 300 Intermarché and Netto shops were hit, along with more than 100 Coopérative U outlets and 80 Carrefour supermarkets. Thierry Cotillard, chief executive of Intermarché, told BFM TV the losses amounted to “tens of millions of euros nationwide in a single day.”

In that case, France’s National Cybersecurity Agency (ANSSI) identified a vulnerability in software supplied by Danfoss, a Danish maker of refrigeration controls. Danfoss said the affected units ran outdated firmware and that it had long advised customers to update or replace older equipment. Blue News reported that older Danfoss controllers no longer receiving security updates, as well as products from Copeland and Dixell, have been among the systems targeted. It is not known which technology Coolworld uses.

Why it matters

Cold rooms in supermarkets, laboratories and hospitals are typically run by control panels connected to the internet so that maintenance contractors can adjust them remotely. That convenience creates an opening for attackers who find a weakness in the software.

CERT-FR, the French government’s computer emergency response team, warned in October that the campaign would likely continue and urged operators to disconnect such systems from the public internet and allow remote access only through secure connections, blue News reported. Steven Lachance, a cybersecurity analyst, told Al Jazeera after the supermarket attacks that the next targets could be energy infrastructure or hospitals, calling the episode “a global wake-up call.”

The attack on the blood service suggests that warning was well founded. Plasma and blood samples are far harder to replace than groceries, and the EFS has for years appealed to the public for more plasma donors.