DD-WRT is a popular open-source firmware installed on many third-party network routers, some of which you may use to connect your devices to your hosting service. A security vulnerability has been identified in this firmware: it contains a stack-based buffer overflow flaw, a type of coding weakness that can be exploited to run unauthorized, malicious code on affected routers. Attackers do not need any login credentials or prior approved access to your network to exploit this flaw. They target the router’s built-in Universal Plug and Play (UPnP) feature, a tool designed to automatically configure network connections for new devices added to your network, to trigger the buffer overflow and execute malicious code on the router. If your router is running vulnerable DD-WRT firmware, a successful attack could allow bad actors to intercept traffic between your devices and your hosting account, alter content on your hosted website, or steal sensitive information tied to your hosting service.
Source: CISA Known Exploited Vulnerabilities Catalog — https://nvd.nist.gov/vuln/detail/CVE-2021-27137