Bryan Cave Leighton Paisner has been sued in a class action lawsuit filed in the Northern District of Illinois following a data breach reported by a client of the law firm.

Plaintiff Augustyn Wiacek, a former employee of snack-food maker Mondelez, brought the suit on behalf of himself and other current and former employees whose personal data were accessed by hackers in late February. According to a data breach report by Mondelez on June 15, more than 51,000 current and former employees’ data were acquired by hackers who breached the defenses of Bryan Cave. According to the complaint, filed on Friday, Bryan Cave was hired to provide data and privacy advice, among other services.