CVE-2025-6486 is a critical stack-based buffer overflow vulnerability identified in the TOTOLINK A3002R router, specifically affecting firmware version 1.1.1-B20200824.0128. The flaw resides in the function formWlanMultipleAP within the /boafrm/formWlanMultipleAP file. The vulnerability is triggered by manipulating the 'submit-url' argument, which leads to a stack-based buffer overflow condition. This type of vulnerability occurs when more data is written to a buffer located on the stack than it can hold, potentially overwriting adjacent memory and allowing an attacker to execute arbitrary code or cause a denial of service. The vulnerability can be exploited remotely without requiring user interaction or authentication, increasing its risk profile. The CVSS v4.0 score is 8.7, indicating a high severity level. The vector string (AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P) shows that the attack can be launched over the network with low attack complexity, no privileges required, and no user interaction needed. The impact on confidentiality, integrity, and availability is high, meaning successful exploitation could lead to full system compromise, data leakage, or service disruption. Although no public exploits are currently known in the wild, the disclosure of the vulnerability and its exploit details increases the likelihood of active exploitation attempts in the near future. No official patches or updates have been linked yet, which leaves affected devices vulnerable if not mitigated by other means.

For European organizations, the impact of this vulnerability could be significant, especially for those relying on TOTOLINK A3002R routers in their network infrastructure. The ability to remotely execute code or cause denial of service on these devices could lead to network outages, unauthorized access to internal systems, and potential lateral movement within corporate networks. This is particularly critical for sectors with high availability and confidentiality requirements such as finance, healthcare, and critical infrastructure. The vulnerability’s remote exploitability without authentication means attackers can target exposed devices directly from the internet or compromised internal networks. Given the router’s role as a network gateway, exploitation could undermine perimeter defenses, exposing sensitive data and disrupting business operations. Additionally, the lack of patches increases the window of exposure, making timely mitigation essential. The public disclosure of the exploit details further raises the risk of opportunistic attacks against unpatched devices across Europe.

1. Immediate network-level mitigation: Block or restrict access to the router’s management interface (typically HTTP/HTTPS ports) from untrusted networks, especially the internet, using firewall rules or network segmentation. 2. Disable or restrict remote management features on the TOTOLINK A3002R devices to minimize exposure. 3. Monitor network traffic for unusual requests targeting the /boafrm/formWlanMultipleAP endpoint or abnormal patterns that could indicate exploitation attempts. 4. Implement intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics to detect attempts to exploit this buffer overflow. 5. If possible, replace affected devices with models from vendors providing timely security updates or with known secure configurations. 6. Regularly audit and inventory network devices to identify all TOTOLINK A3002R routers running the vulnerable firmware version. 7. Engage with TOTOLINK support channels to obtain firmware updates or patches as soon as they become available and apply them promptly. 8. Educate IT staff about this vulnerability and ensure incident response plans include steps for potential exploitation scenarios involving network infrastructure devices.