2016 TeamViewer — corporate network intrusion (Winnti); delayed disclosure to 2019

TeamViewer publicly confirmed in 2019 that its internal corporate network was breached in 2016, with reporting tying the intrusion to Chinese APT–style actors deploying the Winnti backdoor. The firm maintained it found no evidence that customer data, the product environment, or source code was compromised, distinguishing the incident from contemporaneous consumer reports of remote takeovers that TeamViewer attributed to credential reuse and weak passwords. Rows document a confirmed vendor corporate-network compromise with contested downstream data impact.