China has experienced its largest-ever data breach, with approximately 4 billion personal information records leaked online. The compromised data includes detailed user information from popular platforms such as WeChat and Alipay, encompassing account logins, contact lists, message archives, addresses, and financial transaction details. Cybersecurity researchers have described the scale of the exposure as involving "billions upon billions" of data records pertaining to hundreds of millions of Chinese citizens. Russian counterintelligence agents are reportedly analyzing the leaked WeChat data to monitor contacts potentially linked to Chinese spies, according to a Russian intelligence document obtained by The New York Times. This incident marks the most extensive single personal data breach recorded in China to date.