Retailer Dixons Carphone said it has uncovered unauthorised access of data held by the company, involving 5.9 million payment cards and 1.2 million personal data records.
The company said 5.8 million of the payment cards targeted were protected by chip and Pin, but that around 105,000 non-EU cards without chip and Pin protection were compromised.
It said relevant card companies had been notified, but added there was no evidence of fraud on the cards as a result of this incident.
Dixons Carphone said the 1.2 million personal data records that were hacked saw non-financial personal data, such as name, address or email address, accessed.
The group is contacting all those affected, but sought to assure it had no evidence that this had resulted in fraud at this stage.
“We are extremely disappointed and sorry for any upset this may cause,” commented Dixons Carphone’s chief executive Alex Baldock.
“The protection of our data has to be at the heart of our business, and we’ve fallen short here. We’ve taken action to close off this unauthorised access and though we have currently no evidence of fraud as a result of these incidents, we are taking this extremely seriously,” the CEO said.
“We are determined to put this right and are taking steps to do so; we promptly launched an investigation, engaged leading cyber security experts, added extra security measures to our systems and will be communicating directly with those affected,” he stated.