CVE-2025-5793 is a critical buffer overflow vulnerability identified in the TOTOLINK EX1200T router, specifically in firmware version 4.1.2cu.5232_B20210713. The vulnerability resides in an unspecified function within the HTTP POST request handler component, located at the endpoint /boafrm/formPortFw. The flaw is triggered by manipulating the 'service_type' argument in the POST request, which leads to a buffer overflow condition. This vulnerability can be exploited remotely without requiring user interaction or prior authentication, making it highly accessible to attackers. The buffer overflow could allow an attacker to execute arbitrary code on the device, potentially leading to full compromise of the router. The CVSS v4.0 score is 8.7 (high severity), reflecting 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. Although no public exploits are currently known to be in the wild, the exploit code has been disclosed publicly, increasing the risk of imminent exploitation. The vulnerability affects a widely used consumer-grade router model, which is often deployed in home and small office environments, potentially serving as a gateway to internal networks. The lack of available patches at the time of publication further exacerbates the risk.

For European organizations, this vulnerability poses a significant risk, especially for small and medium enterprises (SMEs) and home office users relying on TOTOLINK EX1200T routers. Successful exploitation could lead to unauthorized remote code execution, allowing attackers to intercept, manipulate, or disrupt network traffic, compromise connected devices, and potentially pivot into corporate networks. This could result in data breaches, service disruptions, and unauthorized access to sensitive information. Given the router's role as a network gateway, the compromise could undermine network integrity and availability, impacting business continuity. Additionally, the vulnerability could be leveraged as part of larger botnet campaigns or lateral movement within networks. The public disclosure of exploit details increases the urgency for mitigation to prevent exploitation by less sophisticated attackers.

Organizations and users should immediately verify if their network infrastructure includes the TOTOLINK EX1200T model running the affected firmware version 4.1.2cu.5232_B20210713. In the absence of an official patch, the following specific measures are recommended: 1) Disable remote management interfaces on the router to prevent external exploitation; 2) Restrict access to the router's web management interface to trusted internal IP addresses only; 3) Implement network segmentation to isolate vulnerable devices from critical assets; 4) Monitor network traffic for unusual POST requests targeting /boafrm/formPortFw or anomalous activity indicative of exploitation attempts; 5) Consider replacing affected devices with models from vendors providing timely security updates; 6) Regularly check TOTOLINK's official channels for firmware updates addressing this vulnerability and apply patches promptly once available; 7) Employ intrusion detection/prevention systems (IDS/IPS) with signatures targeting this vulnerability or related exploit attempts; 8) Educate users about the risks of using outdated router firmware and the importance of network device security.