WeChat Zero-Click Worm Took Over Accounts on iPhone and Android via Incoming Calls
Researchers at the security firm Calif have built a worm that takes over a WeChat account via an incoming call and demonstrated it spreading among three test phones. The person being called does not have to answer or touch their phone for it to work, but the caller must already be one of their WeChat contacts. Calif reported the flaw to Tencent in July and says the company has since blocked the exploit for all users. No attacks using the flaw have been reported, and Calif does not say there were any. Attacks that require no action from the target, known as zero-click attacks, are not new. Last year, WhatsApp patched a flaw it said may have been used in targeted attacks. Answering the call does not stop the attack. Calif said a person who picks up hears nothing and the exploit still works. Declining the call ends that attempt, but the attacker can call again later, for example while the target is asleep. The caller has to be on the target's WeChat contac...
Sep 08, 2026