CVE-2025-6164 is a critical buffer overflow vulnerability identified in the TOTOLINK A3002R router, specifically in firmware version 4.0.0-B20230531.1404. The flaw resides in the HTTP POST request handler component, within the /boafrm/formMultiAP endpoint. The vulnerability is triggered by manipulating the 'submit-url' argument in the POST request, which leads to a buffer overflow condition. This type of vulnerability can allow an attacker to overwrite memory, potentially enabling arbitrary code execution or causing a denial of service. The vulnerability is remotely exploitable without requiring user interaction or authentication, increasing the risk profile significantly. Although no known exploits have been observed in the wild yet, the exploit code has been publicly disclosed, which raises the likelihood of imminent attacks. The CVSS 4.0 base score of 8.7 (high severity) reflects the ease of exploitation (network attack vector, low attack complexity), no privileges or user interaction required, and a high impact on confidentiality, integrity, and availability. The vulnerability affects a specific firmware version of the TOTOLINK A3002R, a consumer and small office/home office (SOHO) router model. Given the nature of the flaw, successful exploitation could lead to full compromise of the device, allowing attackers to intercept or manipulate network traffic, pivot into internal networks, or disrupt network availability.

For European organizations, this vulnerability poses a significant risk, especially for small and medium enterprises (SMEs) and home office users relying on TOTOLINK A3002R routers. Exploitation could lead to unauthorized access to internal networks, data exfiltration, or disruption of network services. Critical infrastructure operators or businesses with remote workforces using this router model may face increased exposure. The compromise of network devices can facilitate lateral movement and persistent footholds for attackers, potentially impacting confidentiality and integrity of sensitive data. Additionally, disruption of network availability could affect business continuity. Given the public disclosure of the exploit, threat actors may rapidly weaponize this vulnerability, increasing the urgency for mitigation. The impact is amplified in environments lacking robust network segmentation or monitoring, common in smaller organizations. European entities involved in sectors such as finance, healthcare, and critical infrastructure should be particularly vigilant due to the potential for cascading effects from network device compromise.

1. Immediate firmware upgrade: Check for and apply any patches or updated firmware versions from TOTOLINK addressing CVE-2025-6164. If no patch is available, consider temporary mitigations such as disabling remote management or restricting access to the router's web interface to trusted IP addresses only. 2. Network segmentation: Isolate TOTOLINK A3002R devices from critical network segments to limit potential lateral movement in case of compromise. 3. Access control: Implement strict firewall rules to block unsolicited inbound HTTP POST requests to the /boafrm/formMultiAP endpoint from untrusted networks. 4. Monitoring and detection: Deploy network intrusion detection systems (NIDS) with signatures or heuristics to detect exploitation attempts targeting this vulnerability. 5. Device replacement: For organizations with high security requirements, consider replacing vulnerable TOTOLINK A3002R devices with models from vendors with a stronger security track record and timely patching. 6. User awareness: Educate users about the risks of using outdated router firmware and encourage regular updates. 7. Disable unnecessary services: If feasible, disable the HTTP management interface or restrict it to local management only. These steps go beyond generic advice by focusing on specific controls tailored to the vulnerability's exploitation vector and affected device capabilities.