Company officials say more than half a million Roku accounts have been compromised in a cyberattack.

Roku said hackers gained access to user accounts through stolen login credentials, exploiting people who use the same credentials for different accounts.

Credentials used to access Roku accounts likely came from a data breach on a different site.

In fewer than 400 cases, the hackers used Roku accounts to make purchases on its streaming services but did not access sensitive financial information.

The company is reversing charges and refunding all affected accounts. User passwords were automatically reset.

Roku will reach out to users affected by the hack.