CVE-2025-14964 is a stack-based buffer overflow vulnerability identified in the TOTOLINK T10 router firmware version 4.1.8cu.5083_B20200521. The vulnerability arises from improper handling of the loginAuthUrl parameter passed to the sprintf function in the /cgi-bin/cstecgi.cgi endpoint. Because sprintf does not perform bounds checking, an attacker can craft a malicious request that overflows the stack buffer, potentially overwriting the return address or other control data. This can lead to arbitrary code execution on the device with the privileges of the web server process, which typically runs with elevated rights on embedded devices. The vulnerability is remotely exploitable over the network without requiring authentication or user interaction, making it highly dangerous. The CVSS v4.0 score of 9.3 reflects the ease of exploitation (network vector, no privileges, no user interaction) and the high impact on confidentiality, integrity, and availability. Although no public exploits have been reported yet, the nature of the vulnerability and the critical score suggest that exploitation could lead to full device compromise, enabling attackers to intercept traffic, pivot into internal networks, or disrupt services. The affected product, TOTOLINK T10, is a consumer and small business router, which may be deployed in various organizational environments. The vulnerability resides in the router's web management interface, specifically the CGI script handling authentication URLs, a common attack surface for embedded devices. The lack of patches or official mitigation guidance at the time of publication increases the urgency for defensive measures.

For European organizations, exploitation of CVE-2025-14964 could result in complete compromise of affected TOTOLINK T10 routers, leading to unauthorized access to internal networks, interception or manipulation of sensitive data, and potential lateral movement to other critical systems. This could disrupt business operations, cause data breaches, and damage organizational reputation. Given the router’s role as a network gateway, attackers could establish persistent footholds or launch further attacks such as man-in-the-middle or denial-of-service. Small and medium enterprises, as well as home office setups relying on TOTOLINK T10 devices, are particularly vulnerable due to limited security monitoring and patch management capabilities. The absence of authentication and user interaction requirements lowers the barrier for attackers, increasing the likelihood of automated exploitation attempts. The impact extends beyond confidentiality to integrity and availability, as attackers could modify router configurations or cause device crashes. This threat also poses risks to critical infrastructure sectors in Europe that may use these devices in less monitored environments. The overall impact is severe, necessitating immediate attention from affected organizations.

1. Immediately isolate TOTOLINK T10 routers running the vulnerable firmware from untrusted networks, especially the internet, by disabling remote management features. 2. Implement strict network segmentation to limit access to the router’s management interface only to trusted administrative hosts within the internal network. 3. Monitor network traffic for unusual or malformed HTTP requests targeting /cgi-bin/cstecgi.cgi, particularly those containing suspicious loginAuthUrl parameters, using intrusion detection systems or web application firewalls. 4. If possible, replace vulnerable TOTOLINK T10 devices with alternative hardware that is actively supported and patched. 5. Engage with TOTOLINK or authorized vendors to obtain firmware updates or patches addressing this vulnerability; if unavailable, consider vendor escalation or community advisories. 6. Apply compensating controls such as VPN access for administrative functions and enforce strong authentication mechanisms on management interfaces. 7. Conduct regular security audits and vulnerability scans to detect the presence of vulnerable devices in the network. 8. Educate IT staff on the risks of buffer overflow vulnerabilities and the importance of timely patching and network hygiene. 9. Prepare incident response plans to quickly isolate and remediate compromised devices in case of exploitation. These steps go beyond generic advice by focusing on network-level controls, monitoring specific attack vectors, and vendor engagement.