The U.S. Supreme Court on Monday let Meta Platforms Inc’s (META.O) WhatsApp pursue a lawsuit accusing Israel’s NSO Group of exploiting a bug in its WhatsApp messaging app to install spy software allowing the surveillance of 1,400 people, including journalists, human rights activists and dissidents.

The justices turned away NSO’s appeal of a lower court’s decision that the lawsuit could move forward. NSO has argued that it is immune from being sued because it was acting as an agent for unidentified foreign governments when it installed the “Pegasus” spyware.