CVE-2026-3166 is a buffer overflow vulnerability identified in the Tenda F453 router firmware version 1.0.0.3, specifically within the fromRouteStatic function of the /goform/RouteStatic HTTP endpoint. The vulnerability results from improper validation and handling of the 'page' argument passed to this function, leading to a buffer overflow condition. This flaw allows an attacker to remotely send crafted HTTP requests to the router's management interface, triggering the overflow without requiring authentication or user interaction. The overflow can enable arbitrary code execution or cause the router to crash, resulting in denial of service. The vulnerability is located in the HTTP daemon (httpd) component, which handles web-based management of the device. The CVSS v4.0 score of 8.7 (high severity) reflects the ease of remote exploitation (attack vector: network), no privileges or user interaction needed, and the high impact on confidentiality, integrity, and availability. Although no exploits are currently observed in the wild, a public exploit exists, increasing the likelihood of future attacks. The vulnerability affects only firmware version 1.0.0.3, and no official patch has been linked yet. The exposure of this flaw poses a significant risk to organizations relying on Tenda F453 routers, especially in environments where these devices are accessible from untrusted networks.

The potential impact of CVE-2026-3166 is severe for organizations using the affected Tenda F453 routers. Successful exploitation can lead to complete compromise of the router, allowing attackers to execute arbitrary code with system-level privileges. This can result in interception or manipulation of network traffic, unauthorized access to internal networks, and disruption of network services through denial of service. Given that routers serve as critical network infrastructure, compromise can facilitate lateral movement within corporate networks, data exfiltration, or serve as a foothold for further attacks. The vulnerability's remote exploitability without authentication increases the attack surface, especially for organizations with exposed management interfaces. The availability of a public exploit further elevates the risk of widespread attacks. Organizations in sectors with high dependency on network availability and confidentiality, such as finance, healthcare, and government, face significant operational and reputational risks if exploited.

To mitigate CVE-2026-3166, organizations should first verify if they are running Tenda F453 firmware version 1.0.0.3 and prioritize upgrading to a patched firmware version once available from Tenda. In the absence of an official patch, immediate steps include restricting access to the router's management interface by implementing network segmentation and firewall rules to limit access only to trusted administrative hosts. Disabling remote management over the internet is critical to reduce exposure. Monitoring network traffic for unusual HTTP requests targeting /goform/RouteStatic can help detect exploitation attempts. Employing intrusion detection/prevention systems (IDS/IPS) with signatures for this vulnerability or the known exploit can provide additional protection. Regularly auditing router configurations and applying the principle of least privilege for administrative access will reduce risk. Organizations should also consider replacing affected devices with models that have a stronger security posture if patching is delayed.