CVE-2025-6616 is a critical stack-based buffer overflow vulnerability identified in the D-Link DIR-619L router, specifically version 2.06B01. The flaw exists in the function formSetWAN_Wizard51 located in the /goform/formSetWAN_Wizard51 endpoint. The vulnerability arises due to improper handling of the 'curTime' argument, which can be manipulated by an attacker to overflow the stack buffer. This overflow can lead to arbitrary code execution or cause the device to crash, impacting availability. The vulnerability is remotely exploitable without requiring user interaction or authentication, increasing its risk profile. Although the exploit has been publicly disclosed, there are no confirmed reports of active exploitation in the wild. Importantly, the affected product is no longer supported by D-Link, meaning no official patches or firmware updates are available to remediate this issue. The CVSS v4.0 base score is 8.7 (high severity), reflecting the vulnerability's ease of exploitation (network attack vector, low complexity) and its potential to compromise confidentiality, integrity, and availability at a high level. The lack of support and patch availability significantly elevates the risk for users of this device, as mitigations must rely on network-level controls or device replacement rather than software fixes.

For European organizations, the impact of this vulnerability can be significant, especially for those relying on the D-Link DIR-619L router in their network infrastructure. Successful exploitation could allow attackers to execute arbitrary code remotely, potentially gaining control over the affected device. This could lead to interception or manipulation of network traffic, disruption of internet connectivity, or pivoting to internal networks for further compromise. Given that the device is often used in small office or home office (SOHO) environments, organizations with remote or branch offices using this hardware may face increased risk. The lack of vendor support means that organizations cannot rely on firmware updates to mitigate the issue, increasing the likelihood of prolonged exposure. Additionally, compromised routers could be leveraged in botnets or as entry points for broader attacks against European networks. The confidentiality, integrity, and availability of network communications are all at risk, which could impact business operations, data privacy compliance (e.g., GDPR), and overall cybersecurity posture.

Since no official patches are available due to the product being out of support, European organizations should implement the following specific mitigations: 1) Immediate identification and inventory of all D-Link DIR-619L devices running version 2.06B01 within the network. 2) Network segmentation to isolate these devices from critical infrastructure and sensitive data environments, minimizing potential lateral movement if compromised. 3) Deploy strict firewall rules to restrict inbound access to the router's management interfaces, especially blocking access to the /goform/formSetWAN_Wizard51 endpoint or related HTTP/HTTPS management ports from untrusted networks. 4) Replace affected devices with supported hardware models that receive regular security updates. 5) Monitor network traffic for unusual patterns indicative of exploitation attempts, such as unexpected requests to the vulnerable endpoint or anomalous outbound connections. 6) Employ intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics targeting this vulnerability or exploit attempts. 7) Educate IT staff about the risks associated with unsupported hardware and the importance of timely hardware lifecycle management. These measures go beyond generic advice by focusing on compensating controls and proactive device replacement strategies tailored to this specific vulnerability and product lifecycle status.