CVE-2025-6617 is a critical stack-based buffer overflow vulnerability identified in the D-Link DIR-619L router, specifically affecting firmware version 2.06B01. The flaw resides in the function formAdvanceSetup within the /goform/formAdvanceSetup endpoint. An attacker can exploit this vulnerability by manipulating the 'webpage' argument sent to this function, causing a stack-based buffer overflow. This type of overflow can overwrite adjacent memory on the stack, potentially allowing arbitrary code execution, denial of service, or system compromise. The vulnerability is remotely exploitable without requiring user interaction or authentication, as indicated by the CVSS vector (AV:N/AC:L/AT:N/UI:N/PR:L). Although the exploit has been publicly disclosed, there are no confirmed reports of active exploitation in the wild. The vulnerability affects only devices running the specified outdated firmware version, and the product is no longer supported by D-Link, meaning no official patches or updates are available. The CVSS 4.0 base score is 8.7 (high severity), reflecting the high impact on confidentiality, integrity, and availability, combined with ease of remote exploitation and no user interaction needed. The vulnerability does not require privilege escalation but does require low privileges (PR:L), which may correspond to access to the device's web interface or a similar level of access. The lack of vendor support and patch availability significantly increases the risk for affected users, as mitigation must rely on alternative controls or device replacement.

For European organizations, this vulnerability poses a significant risk, especially for those using the D-Link DIR-619L router with the vulnerable firmware version 2.06B01. Successful exploitation could lead to full compromise of the affected router, enabling attackers to intercept, modify, or disrupt network traffic, launch further attacks within the internal network, or use the device as a foothold for persistent access. This can result in data breaches, service outages, and loss of network integrity. Given the router's role as a network gateway, the impact extends to confidentiality, integrity, and availability of organizational data and services. The fact that the device is no longer supported means organizations cannot rely on vendor patches, increasing exposure. Critical infrastructure, small and medium enterprises, and home office environments using this device are particularly vulnerable. The public disclosure of the exploit code increases the likelihood of opportunistic attacks, including automated scanning and exploitation by threat actors. The vulnerability could also be leveraged in botnet campaigns or ransomware attacks targeting European networks. The overall impact is heightened by the ease of remote exploitation and the absence of required user interaction.

Since no official patches are available due to the product being out of support, affected organizations should prioritize the following mitigations: 1) Immediate replacement of the D-Link DIR-619L routers with supported, updated devices from reputable vendors to eliminate the vulnerable hardware. 2) If replacement is not immediately feasible, restrict remote access to the router’s management interface by disabling WAN-side access and limiting LAN-side access to trusted IP addresses only. 3) Employ network segmentation to isolate vulnerable devices from critical network segments, minimizing lateral movement opportunities. 4) Monitor network traffic for unusual patterns or attempts to access /goform/formAdvanceSetup or other suspicious endpoints indicative of exploitation attempts. 5) Implement intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics capable of detecting buffer overflow attempts targeting this router model. 6) Enforce strong network perimeter defenses and regularly update firewall rules to block known malicious IP addresses and scanning activity. 7) Educate IT staff about the vulnerability and ensure incident response plans include steps for detecting and mitigating exploitation attempts. 8) Maintain up-to-date asset inventories to identify all affected devices and ensure comprehensive remediation. These steps go beyond generic advice by focusing on compensating controls and network-level protections in the absence of vendor patches.