WhatsApp has accused Israeli spyware company Paragon Solutions of conducting a stealthy hacking campaign against nearly 90 users, including journalists and civil society members.

A WhatsApp official told Reuters on Friday that Paragon used a ‘zero-click’ exploit—requiring no user interaction—to compromise devices in more than two dozen countries, including Europe.

Following the attack, WhatsApp sent Paragon a cease-and-desist letter, which has since disrupted the hacking effort.

Citizen Lab, a Canadian cybersecurity watchdog, is assisting those affected. Spyware like Paragon’s is typically marketed to governments for crime-fighting and national security. Still, similar tools have previously been found on the devices of journalists, activists, and even US officials.

Paragon, reportedly acquired by US-based AE Industrial Partners last month, promotes itself as an “ethical” spyware provider, claiming to sell only to stable democracies. However, digital rights groups like Access Now argue WhatsApp’s findings challenge this reputation.

The FBI has not commented on the case. WhatsApp says it remains committed to protecting user privacy and works with law enforcement and industry partners.