The vulnerability identified as CVE-2025-55611 affects the D-Link DIR-619L router running firmware version 2.06B01. It is a buffer overflow vulnerability located in the formLanguageChange function, specifically triggered via the nextPage parameter. Buffer overflow vulnerabilities occur when a program writes more data to a buffer than it can hold, potentially overwriting adjacent memory. In this case, the nextPage parameter is not properly validated or sanitized, allowing an attacker to supply input that exceeds the buffer's capacity. Exploiting this vulnerability could allow an attacker to execute arbitrary code on the affected device, potentially leading to unauthorized control over the router. This could include altering router configurations, intercepting or redirecting network traffic, or using the device as a foothold for further attacks within the network. Although no known exploits are currently reported in the wild, the nature of buffer overflow vulnerabilities makes them attractive targets for attackers due to the possibility of remote code execution. The lack of a CVSS score and absence of patch information suggests this vulnerability is newly disclosed and may not yet have an official fix. The affected firmware version 2.06B01 is specifically mentioned, but no broader version range is provided, indicating the vulnerability may be limited to this or closely related versions. The vulnerability was reserved and published in August 2025, indicating it is a recent discovery.

For European organizations, the impact of this vulnerability could be significant, particularly for those relying on the D-Link DIR-619L router in their network infrastructure. Compromise of these routers could lead to interception of sensitive data, disruption of network services, or unauthorized access to internal systems. Small and medium enterprises (SMEs) and home offices using this router model are especially at risk, as these environments often lack robust network security monitoring and may not promptly apply firmware updates. Additionally, critical sectors such as finance, healthcare, and government agencies could face increased risk if these devices are present in their networks, potentially leading to data breaches or service interruptions. The absence of known exploits currently reduces immediate risk, but the vulnerability's characteristics suggest that exploitation could be feasible by skilled attackers. The potential for remote code execution without authentication would elevate the threat level, enabling attackers to compromise devices from outside the network perimeter. This could facilitate lateral movement within organizational networks, data exfiltration, or launching attacks against other connected systems.

Given the lack of an official patch or CVSS score, European organizations should take proactive and specific mitigation steps. First, identify and inventory all D-Link DIR-619L routers, particularly those running firmware version 2.06B01. If possible, upgrade to a newer firmware version that addresses this vulnerability once available. Until a patch is released, restrict access to the router's management interface by limiting it to trusted internal IP addresses and disabling remote management features. Implement network segmentation to isolate vulnerable devices from critical systems and sensitive data. Employ intrusion detection and prevention systems (IDS/IPS) with signatures or anomaly detection capabilities that could identify attempts to exploit buffer overflow conditions. Regularly monitor network traffic for unusual patterns indicative of exploitation attempts. Additionally, consider replacing affected devices with models that have a stronger security posture if firmware updates are not forthcoming. Educate IT staff about this vulnerability and encourage vigilance for related indicators of compromise. Finally, maintain up-to-date backups of router configurations and network device settings to enable rapid recovery if compromise occurs.