CVE-2025-5910 is a critical buffer overflow vulnerability identified in the TOTOLINK EX1200T router firmware versions up to 4.1.2cu.5232_B20210713. The vulnerability resides in an unspecified functionality related to the HTTP POST request handler component, specifically within the /boafrm/formWsc endpoint. A buffer overflow occurs when an attacker sends a specially crafted HTTP POST request to this endpoint, causing memory corruption. This vulnerability can be exploited remotely without requiring user interaction or authentication, making it highly accessible to attackers. The CVSS 4.0 base score is 8.7 (high severity), reflecting the vulnerability's potential to severely impact confidentiality, integrity, and availability. The vector indicates network attack (AV:N), low attack complexity (AC:L), no privileges required (PR:L), no user interaction (UI:N), and high impact on confidentiality, integrity, and availability (VC:H/VI:H/VA:H). Although no known exploits are currently observed in the wild, the public disclosure of the exploit code increases the risk of imminent exploitation. The vulnerability could allow attackers to execute arbitrary code, cause denial of service, or gain unauthorized control over the device, potentially compromising the entire network segment behind the router. The TOTOLINK EX1200T is a consumer and small office/home office (SOHO) router, often deployed in residential and small business environments. Given the nature of the vulnerability and the device's role as a network gateway, exploitation could lead to network-wide compromise, interception of sensitive data, or pivoting attacks against internal systems.

For European organizations, especially small and medium enterprises (SMEs) and residential users relying on TOTOLINK EX1200T routers, this vulnerability poses a significant risk. Compromise of the router could lead to interception of confidential communications, unauthorized network access, and disruption of internet connectivity. In sectors where data privacy and network availability are critical, such as finance, healthcare, and government services, exploitation could result in data breaches, operational downtime, and regulatory non-compliance under GDPR. Additionally, the ability to remotely exploit this vulnerability without authentication increases the attack surface, potentially enabling widespread automated attacks. The lack of patches currently available exacerbates the risk, as organizations may remain exposed until firmware updates are released and applied. Attackers could also leverage compromised routers as footholds for launching further attacks within corporate networks or as part of botnets targeting European infrastructure.

1. Immediate mitigation should include isolating affected TOTOLINK EX1200T devices from critical network segments to limit potential damage. 2. Network administrators should implement strict firewall rules to restrict inbound HTTP POST requests to the /boafrm/formWsc endpoint or block access to the router's management interface from untrusted networks, especially the internet. 3. Monitor network traffic for unusual POST requests targeting the vulnerable endpoint and deploy intrusion detection/prevention systems (IDS/IPS) signatures tailored to detect exploitation attempts. 4. Encourage users and organizations to check their router firmware version and subscribe to vendor security advisories for timely patch releases. 5. Where possible, replace vulnerable devices with alternative routers that have a proven security track record until a patch is available. 6. Employ network segmentation and zero-trust principles to minimize the impact of a compromised router. 7. Conduct regular security audits and penetration testing to identify and remediate exposure to this and similar vulnerabilities. 8. Educate users about the risks of exposing router management interfaces to the internet and enforce strong administrative credentials.