TLDR
- US agencies warned of an “ongoing cyber threat” to industrial refrigeration systems.
- Hackers are targeting internet-connected temperature controllers in grocery and cold storage sites.
- Attacks have hit stores in France and Ireland, US military bases and a French blood bank.
- Operators are told to take devices off the internet, isolate them and apply updates.
- The US has not named who is behind the hacks, though researchers point to Iran.
The United States government issued a joint warning on Thursday about an “ongoing cyber threat” to industrial refrigeration systems. The FBI, the Cybersecurity and Infrastructure Security Agency, and the departments of health, transport and agriculture signed the statement. It followed a series of hacks on commercial freezers in the United States and Europe.
The @FBI and our partners are seeing malicious cyber activity targeting industrial refrigeration and cold-chain monitoring systems around the world. These systems help keep food, medicine, and other products at safe temperatures and are widely used across critical infrastructure… pic.twitter.com/g0D9xe3OA8
— FBI Cyber Branch (@FBICyberBranch) November 5, 2026
The agencies said unidentified “malicious cyber actors” are going after weak points in electronic temperature controllers. These devices are connected to the internet and used in retail grocery and cold storage sites. The statement gave few details about the hackers.
What officials say hackers can do
If an attack works, the hackers could change the temperature inside a unit. The agencies said this could cause fire hazards, loss of inventory and changes to the service life of the system. A separate fact sheet said hackers may force units into constant heating and defrost cycles.
Chris Butera, the acting executive assistant director for cybersecurity at CISA, said every organization that depends on refrigeration and monitoring systems should assume it could be a target. FBI Cyber Branch Operations Director Brett Leatherman said the government is seeing these systems targeted across critical infrastructure sectors worldwide.
The agencies said the attacks are hitting the food, agriculture, transportation and medicine-shipping industries. Operators were asked to remove their devices from the public internet. They were also told to isolate them from corporate networks and apply software updates quickly.
The departments also urged users to change and strengthen passwords. They said equipment that the vendor no longer supports should be retired.
Waves of attacks across Europe and the US
At least three waves of hacks have hit commercial fridges and freezers in recent months. Reuters first reported last week that Pentagon investigators are treating a string of grocery store refrigeration failures on US military bases in August as a cyberattack. The hacks were first reported by Signal and Silence.
In France, a large attack on October 12 caused refrigerators to defrost at Intermarché and Coopérative U stores. Between 150 and 200 Intermarché stores were hit, along with nearly 100 Coopérative U outlets. The damage reached tens of millions of euros.
BFM TV reported that rival chain E. Leclerc was also affected. It said hackers managed to remotely trigger forced defrosting in many stores.
A blood bank in France was also targeted. Hackers tried to raise the temperature in units holding donated blood. They were stopped before the blood supplies were harmed.
A second wave hit more than 100 stores across Europe on Monday. Two separate waves have allowed hackers to raise temperatures in at least a dozen countries. Food was spoiled and produce was destroyed.
Some of the affected systems were remote-controlled units made by Danish company Danfoss. The company had stopped providing security updates for its customers’ freezers.
The US has not blamed any group or government for the hacks. Security researchers have broadly pointed to Iran. US officials also reportedly suspect Iran.
On Monday, Irish supermarket chain SuperValu said refrigeration systems of one specific model were affected in 13 of its 223 stores. Chilled and frozen products were removed from sale.
