South Korean electronics manufacturer Samsung revealed a hacker accessed the personal data of an unspecified number of its U.S.-based customers, even after improving its cybersecurity systems following a previous breach earlier this year.

Samsung informed customers Friday about the breach, which occurred in late July and was discovered Aug. 4. The company said an unauthorized third party might have accessed customers’ names, contact and demographic information, dates of birth, and product registration information.

Samsung assured customers their credit and debit card information, as well as Social Security numbers, were not accessed. The company said it has taken action to secure the affected systems, engaged with a “leading outside cybersecurity firm,” and is working with law enforcement.