CVE-2025-8169 is a critical buffer overflow vulnerability identified in the D-Link DIR-513 router, specifically version 1.10. The flaw exists in the HTTP POST request handler component, within the function formSetWanPPTPcallback located in the /goform/formSetWanPPTPpath endpoint. The vulnerability arises from improper handling of the 'curTime' argument, which can be manipulated by an attacker to overflow a buffer. This overflow can lead to arbitrary code execution or cause the device to crash, potentially allowing remote attackers to gain control over the affected router without requiring authentication or user interaction. The vulnerability is remotely exploitable over the network, increasing its risk profile. Although the exploit has been publicly disclosed, there are no known exploits actively observed in the wild at this time. Importantly, this vulnerability affects only devices that are no longer supported by D-Link, meaning no official patches or updates are available from the vendor. The CVSS 4.0 base score is 8.7, reflecting high severity with network attack vector, low attack complexity, no privileges or user interaction required, and high impact on confidentiality, integrity, and availability. The vulnerability does not require any special conditions such as scope change or authentication, making it a significant risk for any remaining DIR-513 devices still in operation.

For European organizations, the impact of this vulnerability can be substantial, especially for those still utilizing legacy D-Link DIR-513 routers in their network infrastructure. Successful exploitation could lead to full compromise of the affected device, enabling attackers to intercept, modify, or disrupt network traffic, potentially leading to data breaches or denial of service conditions. Given the router's role as a network gateway, attackers could pivot into internal networks, compromising sensitive systems and data. The lack of vendor support means organizations cannot rely on official patches, increasing the risk of prolonged exposure. This is particularly critical for small and medium enterprises or remote offices that may still use older networking equipment due to budget constraints. Additionally, the public disclosure of the exploit code raises the likelihood of opportunistic attacks targeting vulnerable devices. The disruption or compromise of network infrastructure could affect business continuity, regulatory compliance (e.g., GDPR), and reputation. Organizations with remote or branch offices using these routers are at higher risk, as these devices often have less stringent security monitoring.

Since no official patches are available due to the product being end-of-life, European organizations should prioritize immediate mitigation steps. First, identify and inventory all D-Link DIR-513 devices running firmware version 1.10 or earlier. Replace these devices with modern, supported routers that receive regular security updates. If immediate replacement is not feasible, isolate the vulnerable routers from untrusted networks by restricting inbound traffic to the management interface and disabling unnecessary services such as PPTP WAN configuration endpoints. Implement network segmentation to limit the impact of a compromised device. Employ intrusion detection/prevention systems (IDS/IPS) to monitor for suspicious HTTP POST requests targeting /goform/formSetWanPPTPpath. Regularly review firewall rules to block known exploit patterns. Additionally, enforce strict network access controls and monitor router logs for anomalous activity. Educate IT staff about the risks associated with legacy devices and establish policies to phase out unsupported hardware promptly. Finally, consider deploying network-level mitigations such as web application firewalls (WAF) to filter malicious payloads targeting the vulnerable endpoint.