CVE-2025-55587 is a buffer overflow vulnerability identified in the TOTOLINK A3002R router firmware version 4.0.0-B20230531.1404. The flaw exists in the handling of the hostname parameter within the /boafrm/formMapDelDevice endpoint. Specifically, when processing this parameter, the device fails to properly validate or limit the input size, allowing an attacker to supply crafted input that overflows the buffer. This overflow can lead to a Denial of Service (DoS) condition by crashing the device or causing it to become unresponsive. The vulnerability does not currently have a CVSS score, nor are there known exploits in the wild. The affected version is specifically the firmware version 4.0.0-B20230531.1404, and no patch or mitigation has been publicly disclosed at this time. The vulnerability requires an attacker to send a specially crafted request to the vulnerable endpoint, which is likely accessible via the router's web management interface. There is no indication that authentication is required to trigger the vulnerability, which increases the risk of exploitation if the management interface is exposed externally or accessible from the internal network. The lack of a patch and public exploit means the threat is currently theoretical but should be addressed promptly to prevent potential future exploitation.

For European organizations, the impact of this vulnerability primarily involves potential disruption of network connectivity and availability. The TOTOLINK A3002R is a consumer and small office/home office (SOHO) router, so organizations using these devices for internet access or internal networking could experience network outages or degraded performance if the vulnerability is exploited. This could interrupt business operations, especially for small businesses or remote workers relying on these routers. While the vulnerability does not appear to allow remote code execution or data exfiltration, the resulting DoS could indirectly impact confidentiality and integrity by disrupting security monitoring, VPN connections, or other critical network services. The risk is heightened if the router's management interface is exposed to untrusted networks or if internal threat actors exploit the flaw. Given the widespread use of consumer-grade routers in European homes and small businesses, the vulnerability could affect a broad user base, potentially leading to localized network outages and increased support costs.

Organizations and users should immediately verify if they are running the affected TOTOLINK A3002R firmware version 4.0.0-B20230531.1404. If so, they should restrict access to the router's web management interface by disabling remote management or limiting access to trusted IP addresses only. Network segmentation should be employed to isolate management interfaces from general user networks. Monitoring network traffic for unusual requests to the /boafrm/formMapDelDevice endpoint can help detect attempted exploitation. Since no patch is currently available, users should consider upgrading to a newer firmware version once released or replacing the device with a more secure alternative. Additionally, applying general best practices such as changing default credentials, enabling firewall protections, and regularly updating device firmware will reduce the attack surface. Vendors and security teams should prioritize developing and deploying a firmware update that properly validates input lengths to eliminate the buffer overflow condition.