CVE-2025-61577 identifies a stack overflow vulnerability in the D-Link DIR-816A2 router firmware version FWv1.10CNB05. The flaw exists in the dir_setWanWifi function, which processes the statuscheckpppoeuser parameter. An attacker can craft a specially designed input to this parameter, triggering a stack overflow condition. This overflow can cause the router to crash or reboot, resulting in a Denial of Service (DoS) condition. The vulnerability does not require authentication or user interaction, making it potentially exploitable remotely if the management interface or affected service is exposed. However, no public exploits or active attacks have been reported to date. The vulnerability primarily impacts availability, as it disrupts network connectivity by incapacitating the router. No information about affected firmware versions beyond FWv1.10CNB05 is provided, and no official patches or mitigations have been released yet. The lack of a CVSS score necessitates an independent severity assessment based on the technical details and potential impact.

For European organizations, this vulnerability poses a risk to network availability, particularly for those using the D-Link DIR-816A2 router model in their infrastructure or home office environments. A successful exploit could disrupt internet connectivity, affecting business operations, remote work capabilities, and access to cloud services. Critical sectors such as healthcare, finance, and government agencies relying on stable network infrastructure could experience operational interruptions. Although the vulnerability does not directly compromise data confidentiality or integrity, the resulting DoS could be leveraged as part of a broader attack strategy to cause disruption or distract from other malicious activities. The absence of known exploits reduces immediate risk, but the potential for future exploitation remains, especially if the router is exposed to untrusted networks or the internet. Organizations with poor network segmentation or weak access controls on router management interfaces are at higher risk.

1. Immediately restrict access to the router's management interface by limiting it to trusted internal networks and disabling remote management if not necessary. 2. Monitor D-Link's official channels for firmware updates addressing this vulnerability and apply patches promptly once available. 3. Implement network segmentation to isolate critical systems from consumer-grade routers that may be vulnerable. 4. Employ intrusion detection/prevention systems (IDS/IPS) to monitor for unusual traffic patterns targeting router management services. 5. Conduct regular audits of network devices to identify and replace outdated or unsupported hardware. 6. Educate users and administrators about the risks of exposing router management interfaces to the internet. 7. Consider deploying alternative, more secure network equipment in environments requiring high availability and security.