CVE-2026-3726 identifies a stack-based buffer overflow vulnerability in the Tenda F453 router firmware version 1.0.0.3. The vulnerability is located in the fromwebExcptypemanFilter function, specifically in the handling of the 'page' argument passed to the /goform/webExcptypemanFilter endpoint. Improper validation or sanitization of this input allows an attacker to overflow the stack buffer, potentially overwriting return addresses or control data on the stack. This can lead to arbitrary code execution or cause the device to crash, resulting in denial of service. The vulnerability is remotely exploitable over the network without requiring authentication or user interaction, which significantly increases its risk profile. The CVSS v4.0 score of 8.7 (high severity) reflects the ease of exploitation (network attack vector, low attack complexity), no privileges or user interaction required, and the high impact on confidentiality, integrity, and availability. While no known exploits have been observed in the wild yet, the public disclosure of exploit code means attackers can readily weaponize this vulnerability. The affected product, Tenda F453, is a consumer-grade router commonly used in various regions, making this a concern for both home users and organizations relying on this hardware for network connectivity. No official patches or mitigation links have been provided at this time, increasing the urgency for defensive measures.

The exploitation of CVE-2026-3726 can have severe consequences for organizations and individuals using the Tenda F453 router. Successful exploitation can lead to full compromise of the device, allowing attackers to execute arbitrary code with the privileges of the affected process. This can enable attackers to intercept, modify, or redirect network traffic, steal sensitive information, or pivot into internal networks. Additionally, attackers can cause denial of service by crashing the device, 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 lack of authentication and user interaction requirements lowers the barrier for exploitation, increasing the likelihood of attacks. Organizations relying on Tenda F453 devices for critical communications or internet access face heightened risk of operational disruption and data breaches. The public availability of exploit code further elevates the threat landscape, potentially attracting opportunistic attackers and automated exploit attempts.

To mitigate CVE-2026-3726 effectively, organizations should first verify if they are using Tenda F453 routers with firmware version 1.0.0.3. If so, immediate steps include isolating these devices from untrusted networks and restricting remote management interfaces to trusted IP addresses only. Network segmentation should be employed to limit exposure of vulnerable devices. Monitoring network traffic for unusual activity targeting the /goform/webExcptypemanFilter endpoint can help detect exploitation attempts. Since no official patches are currently available, consider deploying Web Application Firewalls (WAFs) or Intrusion Prevention Systems (IPS) with custom rules to block malicious payloads targeting the vulnerable parameter. Regularly check for firmware updates from Tenda and apply them promptly once released. Additionally, replacing vulnerable devices with updated or alternative hardware should be considered for long-term security. Educating users about the risks and encouraging disabling remote administration features when not needed can reduce attack surface. Finally, maintain robust network backup and recovery procedures to minimize impact in case of compromise.