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 within the /cgi-bin/cstecgi.cgi endpoint. Since sprintf does not perform bounds checking, an attacker can craft a malicious HTTP 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. The vulnerability is remotely exploitable without requiring authentication or user interaction, increasing the attack surface significantly. The CVSS v4.0 score of 9.3 reflects the critical nature of this flaw, with network attack vector, low attack complexity, no privileges or user interaction needed, and high impact on confidentiality, integrity, and availability. While no public exploits have been reported yet, the vulnerability’s characteristics make it a prime candidate for exploitation by threat actors targeting network infrastructure. The TOTOLINK T10 is a consumer and small business router, and compromised devices could be used as entry points into internal networks or for launching further attacks such as lateral movement or data exfiltration.

For European organizations, exploitation of CVE-2025-14964 could lead to full compromise of affected TOTOLINK T10 routers, resulting in unauthorized access to internal networks, interception or manipulation of network traffic, and disruption of network availability. This is particularly concerning for small and medium enterprises (SMEs) and home office environments that rely on these routers without extensive security controls. Critical sectors such as finance, healthcare, and government agencies using these devices may face increased risk of espionage, data breaches, or service outages. The remote and unauthenticated nature of the exploit lowers the barrier for attackers, including cybercriminals and state-sponsored actors. Additionally, compromised routers could be leveraged as part of botnets or for launching distributed denial-of-service (DDoS) attacks, amplifying the threat to broader European network stability.

1. Immediately check for firmware updates from TOTOLINK addressing CVE-2025-14964 and apply patches as soon as they become available. 2. If patches are not yet released, disable remote management interfaces on TOTOLINK T10 devices to reduce exposure. 3. Implement network segmentation to isolate vulnerable routers from critical internal systems. 4. Employ intrusion detection/prevention systems (IDS/IPS) to monitor and block suspicious HTTP requests targeting /cgi-bin/cstecgi.cgi and the loginAuthUrl parameter. 5. Conduct regular network traffic analysis to detect anomalous patterns indicative of exploitation attempts. 6. Replace outdated TOTOLINK T10 devices with more secure alternatives if patching is not feasible. 7. Educate IT staff and users about the risks associated with vulnerable network devices and enforce strong network security policies. 8. Use firewall rules to restrict access to router management interfaces to trusted IP addresses only.