CVE-2025-6615 is a critical stack-based buffer overflow vulnerability identified in the D-Link DIR-619L router, specifically affecting firmware version 2.06B01. The vulnerability resides in the function formAutoDetecWAN_wizard4 within the /goform/formAutoDetecWAN_wizard4 endpoint. The flaw arises from improper handling of the 'curTime' argument, which can be manipulated by an attacker to overflow a 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, making it highly dangerous. Although the affected product is no longer supported by D-Link, the exploit code has been publicly disclosed, increasing the risk of exploitation. The CVSS 4.0 base score is 8.7 (high severity), reflecting the vulnerability's ease of exploitation (network attack vector, low complexity), no privileges or user interaction needed, and its potential to compromise confidentiality, integrity, and availability with high impact. No patches or mitigations have been released by the vendor due to the product's end-of-life status, which complicates remediation efforts. The vulnerability affects only the specific firmware version 2.06B01 of the DIR-619L router, which is a consumer-grade device commonly used in home and small office environments. The lack of vendor support and public exploit availability make this a significant threat to networks still utilizing this hardware and firmware combination.

For European organizations, the impact of CVE-2025-6615 can be substantial, particularly for small businesses, home offices, and any entities still relying on the D-Link DIR-619L router with firmware 2.06B01. Successful exploitation could allow attackers to execute arbitrary code remotely, potentially leading to full compromise of the affected router. This could result in interception or manipulation of network traffic, disruption of internet connectivity, and pivoting into internal networks. Confidentiality could be breached through data interception or man-in-the-middle attacks, integrity compromised by altering network configurations or injecting malicious traffic, and availability impacted by denial-of-service conditions caused by router crashes or reboots. Since the device is often used at network perimeters, exploitation could undermine the security posture of entire organizational networks. The lack of vendor patches increases the risk of persistent exploitation. Additionally, the public availability of exploit code raises the likelihood of opportunistic attacks, including by cybercriminal groups targeting less protected environments. The threat is particularly relevant in sectors with high reliance on stable internet connectivity and sensitive data, such as SMEs, remote workers, and critical infrastructure operators using legacy equipment.

Given the absence of vendor patches, mitigation must focus on compensating controls and risk reduction strategies. First, organizations should identify and inventory all D-Link DIR-619L devices running firmware 2.06B01. Immediate replacement of these devices with supported hardware is the most effective mitigation. If replacement is not immediately feasible, network segmentation should be implemented to isolate vulnerable routers from critical assets and sensitive data. Deploy network-level intrusion detection and prevention systems (IDS/IPS) with signatures or heuristics capable of detecting exploitation attempts targeting the /goform/formAutoDetecWAN_wizard4 endpoint or anomalous traffic patterns. Disable or restrict remote management interfaces on the affected routers, especially WAN-side access, to reduce exposure. Employ strict firewall rules to limit inbound traffic to trusted sources only. Monitor network logs for unusual activity indicative of exploitation attempts. Consider deploying virtual private networks (VPNs) to secure remote access and reduce reliance on vulnerable router functions. Finally, educate users and administrators about the risks associated with legacy devices and the importance of timely hardware lifecycle management.