CVE-2026-3380 is a buffer overflow vulnerability identified in the Tenda F453 router firmware version 1.0.0.3. The vulnerability arises from improper input validation in the frmL7ImForm function, specifically in the handling of the 'page' parameter within the /goform/L7Im endpoint. When an attacker sends a specially crafted request manipulating this parameter, it causes a buffer overflow, which can overwrite memory and potentially allow arbitrary code execution. The vulnerability is remotely exploitable without requiring authentication or user interaction, making it highly accessible to attackers scanning for vulnerable devices on the internet. The CVSS 4.0 base score is 8.7, reflecting its high impact on confidentiality, integrity, and availability, with low attack complexity and no privileges required. Although no known exploits are currently active in the wild, public proof-of-concept exploits exist, increasing the likelihood of exploitation attempts. The vulnerability affects a specific firmware version, and no official patches have been linked yet, necessitating immediate mitigation steps. This flaw could be leveraged to gain full control over the router, enabling attackers to intercept or manipulate network traffic, launch further attacks within the network, or disrupt network services.

The impact of CVE-2026-3380 is significant for organizations and individuals using the Tenda F453 router with firmware version 1.0.0.3. Exploitation can lead to arbitrary code execution on the device, resulting in full compromise of the router. This can allow attackers to intercept sensitive data, modify network traffic, create persistent backdoors, or launch denial-of-service attacks. For enterprises, this could mean exposure of internal network communications, disruption of business operations, and potential lateral movement to other critical systems. For home users, it could result in loss of privacy, unauthorized access to connected devices, and participation in botnets or other malicious activities. The remote and unauthenticated nature of the exploit increases the risk of widespread attacks, especially if automated scanning and exploitation tools are developed. The absence of a patch at the time of disclosure further elevates the threat, making timely mitigation essential to reduce risk.

Given the lack of an official patch at present, organizations should implement several specific mitigations: 1) Immediately isolate or replace Tenda F453 devices running firmware 1.0.0.3 from critical network segments to limit exposure. 2) Restrict remote access to the router’s management interface by disabling WAN-side access or implementing strict firewall rules to block unauthorized inbound traffic to the /goform/L7Im endpoint. 3) Monitor network traffic for unusual or malformed requests targeting the /goform/L7Im path, which may indicate exploitation attempts. 4) Employ network intrusion detection/prevention systems (IDS/IPS) with updated signatures to detect attempts to exploit this vulnerability. 5) Regularly audit and inventory network devices to identify vulnerable Tenda F453 routers and plan for firmware upgrades or device replacement once patches become available. 6) Educate network administrators about this vulnerability and the importance of limiting router management exposure. 7) Consider deploying network segmentation to minimize the impact of a compromised router on critical systems. These targeted actions go beyond generic advice and focus on reducing attack surface and detecting exploitation attempts until a vendor patch is released.