CVE-2025-7794 is a critical stack-based buffer overflow vulnerability identified in the Tenda FH451 router, specifically version 1.0.0.9. The flaw exists in the function fromNatStaticSetting within the /goform/NatStaticSetting endpoint. This vulnerability arises due to improper handling and validation of the 'page' argument, which allows an attacker to overflow the stack buffer. Exploiting this vulnerability can lead to arbitrary code execution on the device with elevated privileges. The attack vector is remote and does not require user interaction or prior authentication, making it highly exploitable. The vulnerability has been publicly disclosed, increasing the risk of exploitation, although no known exploits have been observed in the wild yet. The CVSS 4.0 base score is 8.7, indicating a high severity level with network attack vector, low attack complexity, no privileges required, and no user interaction needed. The impact on confidentiality, integrity, and availability is high, as successful exploitation could allow attackers to take full control of the affected router, potentially leading to network compromise, interception of traffic, or use of the device as a pivot point for further attacks.

For European organizations, the impact of this vulnerability could be significant, especially for small and medium enterprises or home office environments that rely on Tenda FH451 routers for network connectivity. Compromise of these routers could lead to unauthorized access to internal networks, interception of sensitive communications, and disruption of business operations. Critical infrastructure or organizations with remote sites using this device could face increased risk of lateral movement by attackers. Additionally, the lack of authentication and user interaction requirements means that attackers can exploit this vulnerability at scale, potentially affecting multiple organizations simultaneously. The exposure of network devices to the internet or poorly segmented internal networks would exacerbate the impact. Given the router’s role as a network gateway, successful exploitation could undermine the confidentiality, integrity, and availability of organizational data and services.

Immediate mitigation steps include isolating affected Tenda FH451 devices from untrusted networks and restricting access to the /goform/NatStaticSetting endpoint via firewall rules or network segmentation. Organizations should monitor network traffic for unusual activity targeting this endpoint. Since no official patch is currently available, consider replacing affected devices with models from vendors that provide timely security updates. Implement network-level protections such as intrusion detection/prevention systems (IDS/IPS) configured to detect exploitation attempts targeting this vulnerability. Additionally, disable remote management features on the router if not required, and enforce strict access controls to management interfaces. Regularly audit network devices for firmware versions and known vulnerabilities. Finally, maintain an incident response plan to quickly address any signs of compromise related to this vulnerability.