Threat actors linked to a China-aligned espionage group are exploiting a critical vulnerability (CVE-2026-51990) in Tencent’s Sogou Input Method for Windows to deploy the GrayRabbit backdoor. Researchers at cybersecurity company Gen Digital warn that the security issue is a one-click remote code execution (RCE) flaw. "We observed this vulnerability actively exploited in the wild by the UNC3569 threat group to deploy the GRAYRABBIT backdoor through a crafted link," Gen Threat Labs says. Sogou Input Method is a popular Windows application that lets users type Chinese characters using a standard keyboard and also offers a custom link handler and a built-in web browser using an outdated Chromium engine. Developed by Chinese tech giant Tencent, Sogou Input Method reportedly has hundreds of…