CVE-2025-5904 is a critical buffer overflow vulnerability identified in the TOTOLINK T10 router, specifically affecting firmware version 4.1.8cu.5207. The flaw resides in the setWiFiMeshName function within the /cgi-bin/cstecgi.cgi component, which handles POST requests. The vulnerability is triggered by manipulating the device_name argument, causing a buffer overflow condition. This type of vulnerability can lead to arbitrary code execution, denial of service, or system compromise. The attack vector is remote and does not require user interaction or prior authentication, making exploitation straightforward for an attacker with network access to the device. The CVSS 4.0 base score is 8.7 (high severity), reflecting the vulnerability's ease of exploitation (network attack vector, low complexity), no required privileges or user interaction, and high impact on confidentiality, integrity, and availability. Although no public exploits are currently confirmed in the wild, the disclosure of the exploit code increases the risk of active exploitation. The vulnerability affects the POST request handler, which is typically exposed on the device's management interface, often accessible from local networks or potentially from the internet if remote management is enabled. This vulnerability could allow attackers to execute arbitrary commands or crash the device, severely impacting network operations and security.

For European organizations, the impact of CVE-2025-5904 could be significant, especially for those relying on TOTOLINK T10 routers in their network infrastructure. Successful exploitation could lead to unauthorized control over the router, enabling attackers to intercept, modify, or disrupt network traffic, potentially compromising sensitive data and internal communications. This could also serve as a foothold for lateral movement within corporate networks or as a launchpad for further attacks. The disruption of network availability could affect business continuity, particularly for SMEs and enterprises with limited redundancy. Given the critical nature of the vulnerability and the lack of authentication requirements, attackers could exploit this flaw remotely if the device is exposed to untrusted networks. This elevates the risk for organizations with inadequate network segmentation or exposed management interfaces. Additionally, the vulnerability could be leveraged in botnet campaigns or distributed denial-of-service (DDoS) attacks, further amplifying its impact on European digital infrastructure.

To mitigate CVE-2025-5904, organizations should first verify if their TOTOLINK T10 devices are running the affected firmware version 4.1.8cu.5207. Immediate steps include disabling remote management interfaces exposed to the internet to reduce attack surface. Network segmentation should be enforced to isolate management interfaces from general user networks. Monitoring network traffic for unusual POST requests targeting /cgi-bin/cstecgi.cgi can help detect exploitation attempts. Since no official patch links are currently available, organizations should engage with TOTOLINK support channels to obtain firmware updates or security advisories. As a temporary measure, applying firewall rules to restrict access to the router's management interface to trusted IP addresses is recommended. Additionally, organizations should consider replacing vulnerable devices with models from vendors with robust security update policies if patches are delayed. Regular vulnerability scanning and penetration testing focusing on network devices can help identify similar exposures. Finally, maintaining comprehensive network logging and alerting will aid in early detection of exploitation attempts.