CVE-2025-5508 is a cross-site scripting (XSS) vulnerability identified in the TOTOLINK A3002RU router, specifically in version 2.1.1-B20230720.1011. The vulnerability resides in the IP Port Filtering Page component, where improper sanitization of the 'Comment' argument allows an attacker to inject malicious scripts. This flaw can be exploited remotely without authentication, requiring only user interaction to trigger the malicious payload. The vulnerability is rated with a CVSS 4.8 (medium severity) score, reflecting moderate impact and ease of exploitation. The vendor has been notified but has not responded or issued a patch, and no known exploits are currently observed in the wild. The attack vector is network-based (AV:N), with low attack complexity (AC:L), no privileges required (PR:H indicates high privileges required, but the vector states no privileges, so there is a discrepancy; based on CVSS vector PR:H means privileges required), and user interaction is necessary (UI:P). The vulnerability impacts confidentiality and integrity to a limited extent, with no direct impact on availability. Exploiting this vulnerability could allow attackers to execute arbitrary scripts in the context of the router's web interface, potentially leading to session hijacking, unauthorized configuration changes, or further network compromise if the attacker can lure an authenticated user to a malicious page or link. Given the router’s role as a network gateway device, successful exploitation could facilitate lateral movement or data interception within affected networks.

For European organizations, the impact of CVE-2025-5508 depends on the deployment scale of the TOTOLINK A3002RU router. If used in enterprise or critical infrastructure environments, exploitation could compromise network perimeter security by enabling attackers to execute scripts that hijack administrative sessions or alter router configurations. This could lead to unauthorized access, data leakage, or network disruptions. Small and medium-sized enterprises (SMEs) and home offices using this router model may be particularly vulnerable due to less rigorous network security controls. The vulnerability’s requirement for user interaction means phishing or social engineering could be leveraged to trigger the attack, increasing risk in environments with less security awareness. Although no active exploits are known, the public disclosure and lack of vendor response increase the risk of future exploitation. The vulnerability could also undermine trust in network devices and complicate compliance with European data protection regulations such as GDPR if personal data is exposed or network integrity is compromised.

Organizations should immediately identify and inventory all TOTOLINK A3002RU routers running the affected firmware version 2.1.1-B20230720.1011. Since no official patch is available, mitigation should focus on reducing exposure: restrict access to the router’s web management interface to trusted internal networks only, preferably via VPN or secure management VLANs. Disable remote management features if enabled. Implement strict network segmentation to limit the impact of a compromised router. Educate users and administrators about phishing risks and the need to avoid interacting with suspicious links or pages that could trigger the XSS attack. Monitor network traffic and router logs for unusual activity indicative of exploitation attempts. Consider replacing affected devices with models from vendors with active security support if feasible. Additionally, deploy web application firewalls (WAFs) or intrusion prevention systems (IPS) capable of detecting and blocking XSS payloads targeting router interfaces.