Marks & Spencer had to suspend its website for several hours on Tuesday night after an “internal technical problem” meant customers were able to see other people’s details when they logged in to their accounts.
The firm said no details were compromised in the incident, and has apologised to customers for the inconvenience.
Customers who logged on to the site were briefly able to see the last four digits of the payment card of other users, a spokeswoman for Marks & Spencer said. However, some on social media claimed they were able to be see full payment details.
The M&S spokeswoman said: “There were no financial details compromised at all. We weren’t hacked by a third party. It was an internal technical problem.”
Another shopper said she saw other people’s information even when she logged out and in again.
Mandy Green was among a number of consumers calling for the company to provide reassurance that their accounts had not been compromised.
She wrote: “What reassurances are you offering to customers as I now feel that my details could be misused by anyone?”
The company spokeswoman added: “Due to a technical issue we temporarily suspended our website last night. This allowed us to thoroughly investigate and resolve the issue and quickly restore service for our customers. We apologise to customers for any inconvenience caused.”
The glitch follows on from the very public hacking of the TalkTalk website last week, and will raise further questions about online security and the current practices in place.