CVE-2026-3166 is a buffer overflow vulnerability identified in the Tenda F453 router firmware version 1.0.0.3. The vulnerability exists in the fromRouteStatic function of the /goform/RouteStatic HTTP endpoint, part of the router's embedded HTTP server (httpd). Specifically, the flaw is triggered by improper validation and handling of the 'page' argument, which can be manipulated to overflow a buffer in memory. This overflow can corrupt adjacent memory, potentially allowing an attacker to execute arbitrary code remotely or crash the device, leading to denial of service. The vulnerability is exploitable remotely over the network without requiring authentication or user interaction, making it highly accessible to attackers. The CVSS 4.0 vector indicates network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:L), no user interaction (UI:N), and high impact on confidentiality, integrity, and availability (VC:H, VI:H, VA:H). Although no confirmed exploits in the wild have been reported, publicly available exploit code increases the likelihood of exploitation attempts. The vulnerability affects only the specific firmware version 1.0.0.3 of the Tenda F453 router, emphasizing the need for targeted remediation. The absence of official patches at the time of publication necessitates interim mitigations to reduce exposure.

The impact of CVE-2026-3166 is significant for organizations using Tenda F453 routers, especially in enterprise, SMB, and home network environments. Successful exploitation can lead to full compromise of the affected device, allowing attackers to execute arbitrary code with elevated privileges. This can result in unauthorized network access, interception or manipulation of network traffic, lateral movement within internal networks, and persistent footholds. Additionally, exploitation can cause denial of service by crashing the router, disrupting network availability. Given the router's role as a network gateway, compromise can undermine the confidentiality, integrity, and availability of connected systems and data. The remote, unauthenticated nature of the exploit increases risk, as attackers can scan and target vulnerable devices en masse. The availability of public exploit code further elevates the threat level, potentially leading to widespread attacks if unmitigated. Organizations relying on Tenda F453 devices without updated firmware or mitigations face increased exposure to espionage, data breaches, and operational disruptions.

To mitigate CVE-2026-3166, organizations should first check for and apply any official firmware updates or patches released by Tenda addressing this vulnerability. If patches are unavailable, network administrators should implement the following specific measures: 1) Restrict access to the router's management interface by limiting exposure to trusted internal networks only, using firewall rules or access control lists to block external access to the /goform/RouteStatic endpoint. 2) Disable remote management features if not required, especially HTTP-based management interfaces, or switch to secure management protocols such as HTTPS with strong authentication. 3) Employ network segmentation to isolate vulnerable devices from critical assets and sensitive data. 4) Monitor network traffic for anomalous requests targeting the /goform/RouteStatic endpoint or unusual patterns indicative of exploitation attempts. 5) Use intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics tuned to detect buffer overflow attempts against Tenda routers. 6) Consider deploying network-level mitigations such as Web Application Firewalls (WAFs) to filter malicious HTTP requests. 7) Plan for device replacement or upgrade if vendor support is discontinued or patches are not forthcoming. These targeted steps go beyond generic advice by focusing on reducing attack surface and detecting exploitation attempts specific to this vulnerability.