TaxSlayer, a tax preparation software publisher, has informed just shy of 9,000 of its customers about a data breach affecting their personal data.

On January 13 2016, TaxSlayer noticed that a number of its customers’ accounts had been accessed by an unknown party.

In a statement posted online, TaxSlayer said “TaxSlayer identified on January 13, 2016 that an unauthorized third party, whom we believe obtained your username and password from another online service, may have accessed your TaxSlayer account between 10/10/2015 and 12/21/2015. In order to protect your account, we have temporarily disabled access.”

It’s currently unknown where the usernames and passwords were obtained.

Data affected in the breach includes:

Names

Address

Social Security number

Social Security numbers of dependants

Other data contained on 2014 tax return

As you would expect, TaxSlayer is offering a year’s free credit monitoring to those who have been affected.

More on this story will be published once made available.