Some 4.6 million online customers of high-end retailer Neiman Marcus received notifications this week stating their personal information — names, contact information, payment card numbers, gift cards, usernames, passwords, and security question answers — may have been exposed in a data breach that struck in May 2020.

Neiman Marcus said it "recently learned" of the breach, and has notified law enforcement and hired Mandiant to investigate the case. Some 3.1 million payment and virtual gift cards were affected, but more than 85% of them have expired or are invalid, and none of the retailer's branded credit cards were affected.

The retailer has set up a website here for its customers with more details.