While the actual breach might have taken place past year in July, questions remain about when the United Kingdom retailer learned of the incident.
While 5.8 million of these cards have chip and pin protection, there are a total of 105,000 non-EU issued payment cards that do not have that kind of extra security.
In addition to payment card details, the United Kingdom electronics retailer also said the intruder accessed the personal details of over 1.2 million customers.
"We have no evidence that this information has left our systems", the United Kingdom retailer said, adding that it started notifying each of the affected clients. "The protection of our data has to be at the heart of our business, and we've fallen short here", he added.
Dixons Carphone said it had immediately notified the relevant card companies so that they could protect customers.
"Three Californias" initiative qualifies for November ballot
State officials say eligible ballot measures will become qualified on the 131st day prior to the next statewide general election. The initiative proposes the state to be split into three new states: California , Northern California and Southern California .
Carphone Warehouse is one of many High Street retailers feeling the strain of tough economic challenges.
These figures make it one of the largest data breaches involving a United Kingdom company, emerging just weeks after the GDPR data-protection legislation came into effect.
Dixons Carphone said in a statement: "We are contacting those whose non-financial personal data was accessed to inform them, to apologise, and to give them advice on any protective steps they should take".
However, an additional 105,000 cards from outside the European Union - with no chip-and-pin protection - have been compromised as part of the breach.
The compromised data didn't include PIN codes, CVV numbers, or any other personal or authenticating information that could lead to fraudulent use.
Signs display the logo of Dixons Carphone at the company headquarters in London, Britain August 1, 2017.
The breach was now being investigated by police, it said, while regulators had also been informed.
Dixons Carphone had called in cyber experts and added extra security to its systems following the breach, along with the police and relevant authorities.
- The United States, Mexico And Canada Will Host The 2026 World Cup
- What are the US-South Korea war games?
- Fyre Festival Founder Billy McFarland Arrested for New Ticket-Selling Scam
- Net Neutrality Rules Died Today
- UBER to ID drunk Riders
- Michael Cohen ‘Likely’ to Cooperate With Federal Prosecutors
- More Cyberpunk 2077 details surface up
- Trump, Kim commit to 'complete denuclearization' of Korean Peninsula
- Prince George and Princess Charlotte Play at Polo Event
- How Did a Tick Temporarily Paralyze a Little Girl?