Meta Platforms META shares nudged higher Tuesday, brushing off fresh criticism from Elon Musk, who claimed that WhatsApp is not secure and questioned Meta’s long-standing privacy assurances.

The comments stem from a newly filed class-action lawsuit in San Francisco that alleges Meta employees can bypass WhatsApp’s end-to-end encryption through internal access requests. Musk seized on the filing in a viral post on X, warning users away from WhatsApp and even throwing shade at Signal, an app he once endorsed. The attack hit at the heart of Meta’s privacy messaging, particularly in markets like India and Brazil, where WhatsApp is deeply woven into everyday communication.

Meta wasted little time responding. WhatsApp head Will Cathcart pushed back publicly, saying encryption keys live only on users’ devices and that Meta has no way to read messages. A company spokesperson went further, calling the lawsuit baseless and accusing the law firm behind it of chasing headlines rather than facts.