The company says it's advising all customers Friday evening to change their passwords and that it's contacting customers in most of the countries where it operates.
In an email to customers, the company says customers' names, addresses, dates of birth and passwords may have been exposed by the cyberattack. But it says the database that stores customer credit-card information was not affected by the cyberattack.
The Washington, D.C.-based company says it's working with law enforcement officials to investigate the attack.
It's the latest bad news for LivingSocial. Last November, the company announced it was cutting 400 jobs worldwide, as the deals marked continued to face challenges.